Kala namak as lumps and as ground powder.

Black Salt (Kala Namak)

Sodium chloride with sulfur compounds (kiln-fired rock salt) · also called Kala namak, Himalayan black salt, kala loon, sanchal

Black salt, or kala namak, is a kiln-fired rock salt from South Asia with a sulfur, egg-like smell. It is mostly sodium chloride, and cooks use it sparingly in chutneys, raita and vegan egg-style dishes. No trial in people has tested it, and traditional digestive uses are untested. The key caution: it is still salt, so sodium and blood pressure matter as with any salt.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

About Black Salt (Kala Namak)

Kala namak is a kiln-fired rock salt, mostly sodium chloride, with traces of sulfur compounds that give an egg-like smell. Trials show that sodium raises blood pressure whatever the salt, and none tested kala namak. A 2003 German opinion on one sample found no health risk from normal Indian-cooking use but noted limited data on swallowed hydrogen sulfide. Traditional digestive and goitre uses have not been tested in people, and no source measured its iodine. Swallowing a large amount of any salt can poison, especially children.

What kala namak is

Kala namak, also called black salt or Himalayan black salt, is a kiln-fired rock salt used mainly in India, Pakistan, Bangladesh and Nepal. Wikipedia says it is mostly sodium chloride with traces of sodium sulfate, bisulfate, bisulfite, sulfide, iron sulfide and hydrogen sulfide. Iron sulfide gives the dark violet colour and sulfur compounds give the smell.

Wikipedia says it was traditionally made by firing raw salt in a sealed jar with charcoal and herbal materials, and that adding chemicals to pure salt before firing is now common. So products differ, and we read no standard grading. Whole crystals are brown to black; the powder ranges from pink to dark brown.

^{16 12}

How it is used

It is sprinkled sparingly on chutneys, fruit salads, raita and chaat masala, and on tofu for egg-style dishes. The BfR found Indian cooks use very little because larger amounts taste bad.

Ayurveda describes it as a cooling spice, digestive aid and laxative, and some folk use claims it eases gas, heartburn and goitre; the goitre use is called dubious. We found no human study of these uses.

^{12 16 9}

What the research shows

The strongest evidence is about sodium in any salt. A 2020 BMJ meta-analysis of 133 trials found that lower sodium cut systolic pressure by about 4 mmHg and diastolic by about 2 mmHg. No trial tested kala namak.

One lab study of Himalayan black rock salt reported iron, calcium and magnesium, antioxidant activity in test tubes, and lower sodium than sea and pink salt, without figures in its abstract. We read only the abstract and could not tell if the sample was kiln-fired kala namak. Harvard says trace minerals in specialty salts are too small to give substantial benefit.

We found no study of kala namak in people for any health outcome.

^{2 1 13}

Black salt and Himalayan pink salt

Himalayan pink salt is an unfired rock salt coloured by a little iron oxide. Kala namak is fired and carries sulfur compounds. 'Himalayan black salt' is a name used for kala namak, and its powder can look pink, so the two are easy to confuse.

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Health-body statements

WHO recommends adults have under 2,000 mg sodium (under 5 g salt) a day, adjusted downward for children aged 2 to 15, and says all consumed salt should be iodized. The NHS gives 6 g salt a day as the adult maximum and under 1 g for babies. The BfR opinion of 2003 is the only statement we found about kala namak itself. We did not check the FDA, EFSA or India's food authority.

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At a glance

Traditional uses history, not proof

Used sparingly as a condiment in chutneys, raita, chaat masala, fruit and salads (Wikipedia; BfR).
Applied to tofu for egg-like vegan dishes (Wikipedia).
Described in Ayurveda as a cooling spice, digestive aid and laxative, and used for goitre in Jammu, a use called dubious (Wikipedia).

Studied for research

Sodium and blood pressure (applies to all salts), high
'Lower in sodium' claim (one lab abstract), very low
Salt intake in chronic kidney disease (applies to all salts), high
Mineral and antioxidant claims (lab only), very low
Traditional digestive and laxative use, insufficient
Goitre and iodine claim, insufficient
Egg-like flavour in cooking (not a health benefit), insufficient

Main compounds

Sodium chloride (the main part)
Hydrogen sulfide and other sulfur compounds, which give the smell
Iron sulfide, which gives the dark colour
Traces of sodium sulfate, bisulfate, bisulfite and sulfide

Common forms

Whole dark lumps, or ground powder that ranges from pink to dark brown
Traditionally fired in a sealed jar with charcoal and herbal materials; now often pure salt with added chemicals fired
Used as a finishing seasoning, not in large amounts

Research links: BfR (Germany): hydrogen sulfide in black salt, 2003 (German) · WHO: Sodium reduction (fact sheet) · Harvard Nutrition Source: Salt and Sodium · NHS: Salt in your diet · Himalayan black rock salt lab study (abstract) · Salt toxicity: systematic review of case reports (abstract) · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Sodium chloride with sodium sulfate, iron sulfide and other sulfur compounds (kiln-fired rock salt; halite)
Naming authority: Not applicable (mineral and processed salt)
Synonyms: Kala namak; Himalayan black salt; Black salt; Kala loon; Sanchal
Common names: Black salt (English); Kala namak (Hindi (transliterated)); Himalayan black salt (English); Schwarzsalz (German (BfR))
Family or group: Salt (sodium chloride); a processed rock salt
Native range: Used mainly in India, Pakistan, Bangladesh and Nepal; Wikipedia says production is concentrated in Hisar district, Haryana, and that the raw salt came from halite mines in northern India and brine from lakes such as Sambhar and Didwana.
Habitat: Not applicable. It is mined or made from brine and then fired.
Cultivation: Not applicable.
Harvest and processing: Wikipedia says the raw salt was traditionally fired for 24 hours in a sealed ceramic jar with charcoal and small amounts of harad, amla, bahera, babul bark or natron; the fired salt melts, reacts, and is cooled and aged. It says it is now common to add the chemicals to pure salt before firing. Not checked against a primary source.
Look-alikes and adulterants: Name: Himalayan pink salt; Note: A different, unfired rock salt, mostly sodium chloride with a little iron oxide. 'Himalayan black salt' is a name used for kala namak, and its powder can look pink (BfR: reddish grey to pink).; Name: Table salt; Note: Refined, often iodized, no sulfur smell (Harvard).; Name: Other black or dark salts; Note: Other dark salts exist; we read nothing that confirms they are the same product as kala namak.
Sustainability and conservation: Not applicable.

Photographs

Dark lumps and pinkish-brown powder of black salt in a white bowl — Kala namak as lumps and as ground powder.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
South Asian cooking	Used in chutneys, raita, chaat masala, fruit and salads, and in egg-style vegan tofu (Wikipedia). The BfR found Indian cooks use it very sparingly.	s-wiki-kala-namak
Ayurveda and folk use	Wikipedia says it is a cooling spice used as a laxative and digestive aid, for gas and heartburn, and in Jammu for goitre (called dubious). A 1987 review discusses salts named in the old Ayurvedic texts, but its abstract does not say which is kala namak. Dates and texts are NOT verified here.	s-wiki-kala-namak
History of the product	No source we read gives when kala namak was first made or by whom. Any such history is NOT verified.	p22557573

Traditional use shows how it was used. It does not show that it works or is safe today.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Sodium chloride PubChem 5234	inorganic salt	Not applicable (mineral) Mostly. Harvard gives 1,150 to 2,200 mg sodium per teaspoon of black salt.	The salt itself. Its sodium is the part that raises blood pressure at high intakes. ^{16 13 15}	Authoritative guidance
Hydrogen sulfide PubChem 402	sulfur gas	Not applicable About 200 mg per kg in one 2003 imported sample, measured roughly (BfR).	Main contributor to the egg-like smell (Wikipedia). A toxic gas when breathed in high concentrations; swallowed effects are poorly known (BfR). ^{12 16}	Authoritative guidance
Iron sulfide (greigite named by Wikipedia)	inorganic sulfide	Not applicable Not stated in sources read.	Gives the dark violet colour (Wikipedia). The BfR links the reddish colour to iron minerals. ^{16 12}	Secondary source
Sodium sulfate, bisulfate, bisulfite and sulfide	inorganic sulfur salts	Not applicable Traces (Wikipedia). Amounts not stated.	Give a savoury taste and smell; acidic forms give a mild sour note (Wikipedia). The BfR says sulfides form hydrogen sulfide in stomach acid. ^{16 12}	Secondary source

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Blood volume and blood pressure	Not applicable	When the kidneys cannot keep up with extra sodium, the body holds on to water, which raises blood volume and pressure. This is the general sodium explanation; it was not tested for kala namak. ^{15 2}	Authoritative guidance
Release of hydrogen sulfide from sulfur salts	Not applicable	The BfR says sulfides react with stomach acid to form hydrogen sulfide, which is quickly absorbed, mostly turned into sulfate in the liver or into methanethiol and dimethyl sulfide, and cleared by the kidneys in test animals. This is from the BfR's reading of animal data. ¹²	Animal research

Isolated compounds versus whole extracts

Kala namak is a fired mix, so it is not the same as plain sodium chloride, but it is still mostly sodium chloride. The sulfur compounds are present in traces and add smell and taste. Whether they change health effects has not been studied in people. Sodium per teaspoon overlaps with other salts (Harvard).

Nutritional composition

Sodium is an essential nutrient, and deficiency is extremely unlikely in healthy people (WHO). Kala namak is not shown to be a useful source of iodine or minerals.

7benefits and uses looked at

17studies and sources checked

High certaintybest evidence rating found

2lab markers tracked in trials

2 high certainty2 very low certainty3 not enough evidence

What is Black Salt (Kala Namak) good for?

The uses and claims people ask about, and how strong the human evidence is for each. The strongest evidence is about sodium in any salt, not about kala namak. Read it together with the safety section.

Sodium and blood pressure (applies to black salt too)High certaintyKala namak is mostly sodium chloride. Many trials show that eating less sodium lowers blood pressure, including in people on medicines. This is about sodium in any salt. No trial tested kala namak. 'Lower in sodium' claimVery low certaintyOne lab abstract says Himalayan black rock salt had less sodium than sea salt and pink salt, with no figures. Harvard's range for black salt overlaps with other salts. Egg-like flavour in cooking (not a health benefit)Not enough evidenceUsed sparingly in South Asian dishes and in vegan egg-style recipes for its sulfur smell. This is a cooking use, not a health claim. Traditional digestive, laxative and cooling useNot enough evidenceDescribed in Ayurvedic and folk use. We found no human or animal study of these uses. Mineral and antioxidant claims (lab only)Very low certaintyOne lab study found iron, calcium, magnesium and antioxidant activity in test tubes, with no amounts given. Harvard says trace minerals in specialty salts are too small to matter. Goitre and iodine claimNot enough evidenceA folk goitre use is called dubious. No source measured iodine in kala namak, so do not rely on it for iodine. Salt intake in chronic kidney disease (applies to black salt too)High certaintyIn kidney disease, cutting salt lowered blood pressure and urine protein but raised the chance of low-blood-pressure symptoms. This is about salt in general.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Sodium and blood pressure (applies to black salt too)

High certainty

Black salt is mostly sodium chloride, so it carries the same link between sodium and blood pressure as other salts. Trials show that eating less sodium lowers blood pressure. No trial tested kala namak itself. This is the strongest evidence on this page, and it is about sodium, not about kala namak being special.

4 studiesSalt as a seasoning. These trials did not test kala namak or any one …

Studies, doses and limits

What the trials found

A 2020 BMJ meta-analysis of 133 randomised trials (12,197 adults), a 2024 meta-analysis of 35 trials in people already on blood-pressure medicines, and WHO guidance. All tested sodium or salt in general. No study tested kala namak.

Results

Lower sodium cut systolic pressure by 4.26 mmHg and diastolic by 2.07 mmHg on average (BMJ 2020). Among people on steady medicines, each 100 mmol cut in 24-hour urinary sodium lowered systolic pressure by 6.81 mmHg (2024).

Effect sizes as reported

A few mmHg on average; larger in older people, people with higher starting pressure and non-white populations.

Why this rating

Many randomised trials and several meta-analyses agree, but for sodium in general. For kala namak itself there is no trial.

Form and dose studied

Salt as a seasoning. These trials did not test kala namak or any one salt, and no amounts are advised here.

Who was studied

Adults with and without high blood pressure, including people on blood-pressure medicines.

Limits

Trials are short, and food was often supplied. They tell us about sodium, not about the sulfur compounds in kala namak.

Why researchers looked

High blood pressure is a leading cause of heart disease and stroke. WHO says the main health effect of high-sodium diets is raised blood pressure.

Traditional use

No source read links traditional use of kala namak to blood pressure.

Proposed mechanism Pharmacological theory

Extra sodium makes the body hold more water, which raises blood volume and pressure. This is the general explanation for sodium; it was not tested for kala namak.

A proposed mechanism does not show that the effect happens in people.

Kala namak is still salt. Harvard lists black salt at 1,150 to 2,200 mg of sodium per teaspoon, a range that overlaps with other salts, so read the label and ask your clinician about your own limit.

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'Lower in sodium' claim

Very low certainty

One lab study reported that Himalayan black rock salt had lower sodium than common sea salt and Himalayan pink salt. The abstract gives no figures, and Harvard's range for black salt overlaps with other salts. Treat the claim as unproven and still count it as a salty food.

2 studiesSalt as sold. No amounts are advised.

Studies, doses and limits

What the trials found

No human study. One laboratory study (Chander 2020) measured elements in Himalayan black rock salt. Harvard's table gives teaspoon figures for black salt.

Results

Chander and colleagues report lower sodium than common sea salt and Himalayan pink salt, with no percentage in the abstract. Harvard lists 1,150 to 2,200 mg sodium per teaspoon for black salt against 2,200 for pink and 2,300 for fine iodized table salt; teaspoon figures depend on grain size.

Effect sizes as reported

Not given in the abstract.

Why this rating

One lab abstract without numbers, from a sample that may not be the cooking product; no human data.

Form and dose studied

Salt as sold. No amounts are advised.

Who was studied

None; no human outcome.

Limits

The lab paper's abstract gives no figures, sample number or origin. A lower teaspoon weight can simply mean finer or lighter grains.

Why researchers looked

Sellers say black salt is a lower-sodium salt. A lab study compared its elements with other salts.

Traditional use

No traditional source read makes this claim.

Proposed mechanism Lab measurement

A lab measurement of the sodium content of a sample. It is not a mechanism.

A proposed mechanism does not show that the effect happens in people.

Do not assume black salt can replace a low-sodium plan. Check the label for sodium per serving.

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Egg-like flavour in cooking (not a health benefit)

Not enough evidence

Kala namak is mainly used for its sulfur smell and taste, which many cooks use to give vegan dishes an egg-like flavour. This is a cooking use, not a health claim.

2 studiesSprinkled sparingly on food.

Studies, doses and limits

What the trials found

No health study. The BfR statement and an encyclopedia page describe the culinary use.

Results

The BfR found Indian cooks use it very sparingly because larger amounts taste bad.

Effect sizes as reported

Not applicable.

Why this rating

It is a cooking use. No health outcome was measured, so there is nothing to rate beyond the description.

Form and dose studied

Sprinkled sparingly on food.

Who was studied

Not applicable.

Limits

Descriptions come from one government statement and a secondary source.

Why researchers looked

People use it for taste in chutneys, raita, chaat masala and egg-style tofu dishes.

Traditional use

Used mainly in South Asian cooking (Wikipedia; BfR).

Proposed mechanism Pharmacological theory

The smell comes mainly from sulfur compounds, with hydrogen sulfide the most prominent (Wikipedia). The BfR could not say which compound in the salt releases it.

A proposed mechanism does not show that the effect happens in people.

A salty condiment still adds sodium; use sparingly, as cooks do.

^{12 16}

Traditional digestive, laxative and cooling use

Not enough evidence

Kala namak is described as a cooling spice used as a digestive aid and laxative in Ayurveda, and for easing gas and heartburn. We found no human study testing these uses.

2 studiesNot applicable.

Studies, doses and limits

What the trials found

None. No human or animal trial of kala namak for digestion was found.

Results

No results to report.

Effect sizes as reported

Not applicable.

Why this rating

Only descriptions of tradition; no trial.

Form and dose studied

Not applicable.

Who was studied

Not applicable.

Limits

The only direct sources are an encyclopedia page and a historical abstract. We could not match the Ayurvedic salt names to today's kala namak.

Why researchers looked

Traditional use in South Asia.

Traditional use

Wikipedia describes Ayurvedic use as a cooling spice, laxative and digestive aid and says it is also noted to relieve flatulence and heartburn. A 1987 review (Mooss) discusses named salts in the old Ayurvedic texts, but its abstract does not say which one is kala namak.

Proposed mechanism Traditional use claim

Not tested. No mechanism was established for these uses.

A proposed mechanism does not show that the effect happens in people.

Kala namak is still salt; see the Safety tab.

^{16 9}

Mineral and antioxidant claims (lab only)

Very low certainty

A 2020 lab study of Himalayan black rock salt found iron, calcium and magnesium and antioxidant activity in test-tube methods. The abstract gives no amounts, it tested no people, and Harvard says the trace minerals in specialty salts are too small to give substantial benefit.

2 studiesSalt as sold. No amounts are advised.

Studies, doses and limits

What the trials found

No human study. One lab study (Chander 2020).

Results

The authors found iron, calcium, magnesium and antioxidant activity in vitro and called these beneficial. The abstract gives no amounts. Harvard says (about sea and Himalayan salts, not tested on kala namak) that the amount of minerals in less processed salts is not enough to give substantial nutritional benefit.

Effect sizes as reported

Not given.

Why this rating

Test-tube result from one lab abstract with no amounts; Harvard's general statement points to trace amounts.

Form and dose studied

Salt as sold. No amounts are advised.

Who was studied

None; no human outcome.

Limits

Sample number, origin and whether it was kiln-fired are not stated in the abstract. The authors' words about benefit are their opinion.

Why researchers looked

Sellers say black salt is rich in minerals and antioxidants.

Traditional use

No traditional source read makes this claim.

Proposed mechanism Laboratory research

Test-tube antioxidant assays measure how a sample reacts with chemicals. They do not show an effect in the body.

A proposed mechanism does not show that the effect happens in people.

Salt is still mostly sodium chloride; see the Safety tab. No claim is made that it supplies minerals you need.

^{1 13}

Goitre and iodine claim

Not enough evidence

Folk use for goitre is described as dubious: goitre mostly comes from too little iodine, and a salt helps only if it contains iodide. We found no source that measured iodine in kala namak.

2 studiesNot applicable.

Studies, doses and limits

What the trials found

None. No human study and no iodine measurement.

Results

No results to report.

Effect sizes as reported

Not applicable.

Why this rating

Folk claim with no testing, and no iodine data.

Form and dose studied

Not applicable.

Who was studied

Not applicable.

Limits

Iodine content of kala namak is unknown from the sources read.

Why researchers looked

A folk claim for goitre is reported for the Jammu region.

Traditional use

Wikipedia says it is used in Jammu for goitre and says this use is dubious.

Proposed mechanism Pharmacological theory

Goitre from iodine shortage needs iodine. No measurement of iodine in kala namak was found.

A proposed mechanism does not show that the effect happens in people.

Do not rely on kala namak for iodine. WHO says all salt consumed should be iodized.

^{16 15}

Salt intake in chronic kidney disease (applies to black salt too)

High certainty

In chronic kidney disease, trials of cutting salt lowered blood pressure and protein in the urine, but also raised the chance of symptoms of low blood pressure. This is about salt in general. No study tested kala namak.

1 studiesSalt reduction in general. Amounts are for the clinician.

Studies, doses and limits

What the trials found

A 2021 Cochrane review of 21 trials in 1,197 adults with chronic kidney disease.

Results

Cutting salt by about 4.2 g a day lowered blood pressure by 6.91/3.91 mmHg (high certainty). Urine protein fell by 36% (95% CI 26 to 44) in earlier-stage disease (high certainty). Symptomatic low blood pressure was more likely (RR 6.70; moderate certainty). Trials were too short to test kidney decline or deaths.

Effect sizes as reported

Blood pressure about 7/4 mmHg lower; urine protein 36% lower.

Why this rating

The Cochrane review rates the blood-pressure and urine-protein results as high certainty, for salt in general over the short term.

Form and dose studied

Salt reduction in general. Amounts are for the clinician.

Who was studied

Adults with chronic kidney disease (earlier stages, dialysis, after transplant).

Limits

Trials lasted 1 to 36 weeks. Nothing about kala namak, which is not a low-sodium food.

Why researchers looked

Salt raises blood pressure, and blood pressure harms kidneys.

Traditional use

Not applicable.

Proposed mechanism Pharmacological theory

Less sodium lowers blood pressure and the leak of protein from damaged kidneys.

A proposed mechanism does not show that the effect happens in people.

People with kidney disease should ask their kidney clinician about salt; the right level is individual.

⁷

Connections to the rest of health

How Black Salt (Kala Namak) connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Blood Pressure Support	Demonstrated clinical effect	High certainty	Sodium and blood pressure (applies to black salt too): Black salt is mostly sodium chloride, so it carries the same link between sodium and blood pressure as other salts. Trials show that eating less sodium lowers blood pressure. No trial tested kala namak itself. This is the strongest evidence on this page, and it is about sodium, not about kala namak being special.	^{2 11 15 13}
Heart Health	Demonstrated clinical effect	High certainty	Sodium and blood pressure (applies to black salt too): Black salt is mostly sodium chloride, so it carries the same link between sodium and blood pressure as other salts. Trials show that eating less sodium lowers blood pressure. No trial tested kala namak itself. This is the strongest evidence on this page, and it is about sodium, not about kala namak being special.	^{2 11 15 13}
Blood Pressure Support	Potential benefit	Very low certainty	'Lower in sodium' claim: One lab study reported that Himalayan black rock salt had lower sodium than common sea salt and Himalayan pink salt. The abstract gives no figures, and Harvard's range for black salt overlaps with other salts. Treat the claim as unproven and still count it as a salty food.	^{1 13}
Digestive Health	Traditional use	Not enough evidence	Traditional digestive, laxative and cooling use: Kala namak is described as a cooling spice used as a digestive aid and laxative in Ayurveda, and for easing gas and heartburn. We found no human study testing these uses.	^{16 9}
Thyroid Support	Traditional use	Not enough evidence	Goitre and iodine claim: Folk use for goitre is described as dubious: goitre mostly comes from too little iodine, and a salt helps only if it contains iodide. We found no source that measured iodine in kala namak.	^{16 15}
Kidney Support	Demonstrated clinical effect	High certainty	Salt intake in chronic kidney disease (applies to black salt too): In chronic kidney disease, trials of cutting salt lowered blood pressure and protein in the urine, but also raised the chance of symptoms of low blood pressure. This is about salt in general. No study tested kala namak.	⁷

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Cardiovascular system	Adverse effect or risk	High certainty	Sodium raises blood pressure; kala namak is mostly sodium chloride and was never tested alone. Preparation or compound: Sodium (any salt)	^{2 5 15}
Kidney and urinary system	Contraindication	High certainty	Salt reduction lowers blood pressure and urine protein in kidney disease, with a risk of low-blood-pressure symptoms. Preparation or compound: Sodium (any salt)	⁷
Cardiovascular System	Biological association	High certainty	Studied for: Sodium and blood pressure (applies to black salt too) Studied for: 'Lower in sodium' claim	^{2 11 15 13 1}
Digestive System	Biological association	Not enough evidence	Studied for: Traditional digestive, laxative and cooling use	^{16 9}
Endocrine System	Biological association	Not enough evidence	Studied for: Goitre and iodine claim	^{16 15}
Kidney Urinary	Biological association	High certainty	Studied for: Salt intake in chronic kidney disease (applies to black salt too)	⁷

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Essential hypertension	Adverse effect or risk	High certainty	High sodium raises blood pressure. Preparation or compound: Sodium (any salt)	^{2 11}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Systolic blood pressure	Biological association	High certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{2 11}
Albuminuria (protein in the urine)	Biological association	High certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Fluid balance and blood pressure regulation	Preliminary mechanism	Authoritative guidance	Excess sodium increases fluid held in the body and blood pressure.	^{15 2}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Hydrogen sulfide		Not enough evidence	Gives the smell; one 2003 German opinion found no risk from normal seasoning but noted limited data on swallowed amounts. Preparation or compound: Kala namak sulfur compounds	¹²
Sodium chloride	Biological association	Authoritative guidance	The salt itself. Its sodium is the part that raises blood pressure at high intakes. Preparation or compound: Not applicable (mineral)	^{16 13 15}
Hydrogen sulfide	Biological association	Authoritative guidance	Main contributor to the egg-like smell (Wikipedia). A toxic gas when breathed in high concentrations; swallowed effects are poorly known (BfR). Preparation or compound: Not applicable	^{12 16}
Iron sulfide (greigite named by Wikipedia)	Biological association	Secondary source	Gives the dark violet colour (Wikipedia). The BfR links the reddish colour to iron minerals. Preparation or compound: Not applicable	^{16 12}
Sodium sulfate, bisulfate, bisulfite and sulfide	Biological association	Secondary source	Give a savoury taste and smell; acidic forms give a mild sour note (Wikipedia). The BfR says sulfides form hydrogen sulfide in stomach acid. Preparation or compound: Not applicable	^{16 12}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 2 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Other2

The evidence

The research centre for Black Salt (Kala Namak). Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Sodium and blood pressure (applies to black salt too) 4 studies High certainty 'Lower in sodium' claim 2 studies Very low certainty Egg-like flavour in cooking (not a health benefit) 2 studies Not enough evidence Traditional digestive, laxative and cooling use 2 studies Not enough evidence Mineral and antioxidant claims (lab only) 2 studies Very low certainty Goitre and iodine claim 2 studies Not enough evidence Salt intake in chronic kidney disease (applies to black salt too) 1 studies High certainty

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed and Europe PMC for kala namak and black salt, read the abstracts of the PubMed papers, read the German BfR statement in full, and read the WHO, NHS, Harvard, Poison Help and Wikipedia pages. We checked PubChem for the chemical names. Certainty ratings are the compiler's own reading. Where the sodium and blood pressure evidence is rated high, that is for sodium in general, not for kala namak. Lab surveys use a few samples and may not describe the kiln-fired product. No study is cited that we could not verify.

Study library: every study we checked 17

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Chander 2020 Structural characterization of Himalayan black rock salt by SEM, XRD and in-vitro antioxidant activity Science of the Total Environment · PMID 32798866 · DOI	Lab study n/a	Samples of 'Himalayan black rock salt' (number and source not stated in the abstract)	n/a n/a n/a n/a · vs n/a	Crystals were irregular and cubic. The salt showed antioxidant activity in test-tube methods and, the authors say, lower sodium than common sea salt and Himalayan pink salt. It also contained iron, calcium and magnesium. The abstract gives no amounts. The authors call the minerals beneficial and the salt superior to other table salts; that is their opinion, not a tested health result. Lab description only; no people were tested Methods, limits and funding Outcomes: Crystal shape, mineral structure, elements by atomic absorption, and antioxidant activity in test tubes Limitations: One lab study. The abstract gives no figures, no number of samples and no origin; it does not say whether the salt was the kiln-fired kala namak sold for cooking. Funding not stated in the abstract. The full text was not read. Read: abstract
Huang 2020 Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials BMJ · PMID 32094151 · DOI	Systematic review	12197 133 trials, 12,197 adults, with and without high blood pressure	n/a n/a n/a n/a · vs n/a	Lower sodium cut systolic pressure by 4.26 mmHg (95% CI 3.62 to 4.89) and diastolic by 2.07 mmHg (1.67 to 2.48). Each 50 mmol drop in 24-hour urinary sodium cut systolic pressure by 1.10 mmHg. The fall was larger in older people, non-white populations and people with higher starting pressure. Short trials (under 15 days) underestimated the effect. Less sodium lowers blood pressure (SBP -4.26 (-4.89 to -3.62); DBP -2.07 (-2.48 to -1.67)) Methods, limits and funding Outcomes: Systolic and diastolic blood pressure after lower versus usual sodium Limitations: Trials tested sodium or salt in general, never kala namak. Read: abstract
Hull 2025 Salty Despair: An Adolescent's Suicide Attempt through Salt Overdose Psychopharmacology Bulletin · PMID 39744409 · DOI	Case report	1 One adolescent girl	n/a n/a n/a n/a · vs n/a	She swallowed about 4 dessertspoons (2 to 3 tablespoons) of kosher salt and recovered without signs of brain damage. The authors say 2 to 4 tablespoons taken rapidly can be lethal, depending on age and size. A large single intake of salt can be life-threatening Methods, limits and funding Outcomes: Outcome after swallowing about 4 dessertspoons of kosher salt Limitations: One case; kosher salt, not kala namak. The paper is about self-harm; if you are struggling, contact a crisis line or emergency services in your country. Read: abstract
Kakoo Brioso 2022 Salt Poisoning Due to Inadequate Infant Formula Preparation: A Rare Cause of Hypernatremia and Massive Cerebral Hemorrhage in a Newborn Cureus · PMID 36721612 · DOI	Case report	1 One newborn	n/a n/a n/a n/a · vs n/a	A newborn with lethargy and poor feeding had blood sodium of 174 mmol/L, then convulsive status epilepticus and bleeding in the brain. The parents had mixed too much powder into the formula. After careful correction of the sodium and seizure medicine the baby improved and went home. Salt poisoning in a baby from a mixing mistake Methods, limits and funding Outcomes: Blood sodium, seizures, brain imaging Limitations: One case; formula, not kala namak. Read: abstract
Kong 2025 Dietary salt intake and cardiovascular outcomes: an umbrella review of meta-analyses and dose-response evidence Annals of Medicine · PMID 41243115 · DOI	Systematic review	21 meta-analyses of trials and observational studies (91 outcomes)	n/a n/a n/a n/a · vs n/a	High salt intake went with more cardiovascular disease (RR 1.13, 95% CI 1.06 to 1.20), hypertension (OR 1.33), stroke (OR 1.34) and stroke death (OR 1.40). Each extra 1 g a day of sodium raised systolic pressure by 0.60 mmHg and cardiovascular and stroke risks by 4% and 6%. Low intake went with lower cardiovascular death (RR 0.83) and all-cause death (RR 0.88). High salt intake raises cardiovascular risk (CVD RR 1.13 (1.06 to 1.20)) Methods, limits and funding Outcomes: Heart disease, stroke, death and blood pressure by salt intake Limitations: Mixes trials with observational studies, which cannot prove cause. The authors note that effects of both high and low sodium are debated. Funding and conflicts: Research support, non-US government (as listed by PubMed). Read: abstract
Kuttykattil 2023 Consuming microplastics? Investigation of commercial salts as a source of microplastics (MPs) in diet Environmental Science and Pollution Research · PMID 35907067 · DOI	Product analysis n/a	Australian commercial salts, land-mined and marine, including one black salt	n/a n/a n/a n/a · vs n/a	Of 90 suspected particles, 78.8% were confirmed as microplastics (23.2 micrometres to 3.9 mm). Coarse Himalayan pink salt had the highest load (174.04 particles per kg), then black salt (157.41 +/- 23.13 per kg). The average for all salts was 85.19 per kg. The authors say this is the first detection of microplastics in black salt and that land-mined salts (such as black and Himalayan) had more than marine salt. Effects on health are unknown. Microplastics were found in the black salt tested Methods, limits and funding Outcomes: Microplastic particles per kilogram of salt Limitations: A few brand samples from one country. The abstract does not say whether the black salt was kiln-fired kala namak. Only the abstract was read. Read: abstract
McMahon 2021 Altered dietary salt intake for people with chronic kidney disease (Cochrane review) Cochrane Database of Systematic Reviews · PMID 34164803 · DOI	Systematic review	1197 21 trials, 1,197 adults with chronic kidney disease (12 earlier stages, 7 dialysis, 2 after transplant)	n/a n/a n/a n/a · vs n/a	Cutting salt by about 4.2 g a day (1,690 mg sodium) lowered blood pressure by 6.91/3.91 mmHg (high certainty). Albuminuria fell by 36% (95% CI 26 to 44) in six trials, five in earlier-stage disease (high certainty). Lower salt may cause symptoms of low blood pressure (RR 6.70, 95% CI 2.40 to 18.69; moderate certainty). Trials were too short (1 to 36 weeks) to test deaths, heart events or kidney decline. Salt reduction lowers blood pressure and urine protein in kidney disease, with a risk of low-blood-pressure symptoms (SBP/DBP -6.91/-3.91 mmHg; albuminuria -36% (26 to 44)) Methods, limits and funding Outcomes: Blood pressure, protein in the urine (albuminuria), fluid, symptoms of low blood pressure Limitations: Short trials; sparse data on other harms. Salt in general, not kala namak. Read: abstract
Metheny 2020 Salt Toxicity: A Systematic Review and Case Reports Journal of Emergency Nursing · PMID 32340735 · DOI	Systematic review	15 15 case reports (ages 5 days to 73 years) of a large salt load swallowed over minutes to hours	n/a n/a n/a n/a · vs n/a	Salt toxicity is a rare, dangerous rise in blood sodium that can cause serious brain injury. Of 14 cases with known outcomes, 50% were fatal. Forty percent of patients were children under 15. Common causes were salt water used to make someone vomit, a caregiver giving a child a large amount of salt, and suicide attempts. Fast treatment may prevent lasting brain injury. Rare but often fatal after a large single intake of any salt Methods, limits and funding Outcomes: Causes, symptoms and outcomes of salt toxicity Limitations: Case reports only, 2000 to 2019; 15 cases. It is about salt in general. Read: abstract
Mooss 1987 Salt in ayurveda I Ancient Science of Life · PMID 22557573	Narrative review n/a	Ayurvedic texts (Susruta, Caraka, Vagbhata)	n/a n/a n/a n/a · vs n/a	The abstract says the old texts describe specific salts, including Saindhava, Samudra, Vida, Sauvarcha and others, with their properties and actions, discusses them in terms of chemical constituents, and points out 'evidently spurious' methods of making them. It does not say which of these is kala namak, and it gives no health findings. Describes traditional texts; no trial Methods, limits and funding Outcomes: Properties and actions of named salts (Lavanam), compared with present preparation methods Limitations: Abstract only (no full text). A 1987 historical review. It does not match any named salt to today's kala namak. Read: abstract
Pai 2024 Analysis of Fluoride Content of Different Types of Salts Used in the Indian Diet: An In Vitro Study Cureus · PMID 39246882 · DOI	Product analysis n/a	8 Four salt types (iodized, rock, pink, black), two market brands of each, India	n/a n/a n/a n/a · vs n/a	Black salt had the highest fluoride, 77.5 +/- 19.9 ppm, against 12.5 +/- 7.5 ppm for iodized salt and 40.8 +/- 52.4 ppm for rock salt (p=0.009 across groups). The authors say all values were well within the prescribed limits and call for fluoride labelling. Fluoride varied by salt type; black salt was highest Methods, limits and funding Outcomes: Fluoride in parts per million Limitations: Only two brands per type, so eight samples in all; a simple colour-test method. Funding not stated in the abstract. The abstract does not say whether the black salt was kiln-fired kala namak. Only the abstract was read. Read: abstract
Song 2024 Blood Pressure-Lowering Medications, Sodium Reduction, and Blood Pressure Hypertension · PMID 39236753 · DOI	Systematic review	2885 35 trials, 2,885 people with high blood pressure on steady blood-pressure medicines	n/a n/a n/a n/a · vs n/a	For every 100 mmol drop in 24-hour urinary sodium, systolic pressure fell by 6.81 mmHg (95% CI 4.96 to 8.66) and diastolic by 3.85 mmHg (2.26 to 5.43). The effects were larger with beta-blockers, renin-angiotensin-aldosterone system inhibitors and two-drug treatment. Less sodium lowers blood pressure further even in treated people (SBP -6.81 per 100 mmol (-8.66 to -4.96)) Methods, limits and funding Outcomes: Blood pressure after less sodium (24-hour urine sodium) Limitations: Trials used sodium in general. Median length 28 days. Read: abstract
n/a 2003 Bundesinstitut fuer Risikobewertung (BfR, German Federal Institute for Risk Assessment): Vorkommen von Schwefelwasserstoff in 'Schwarzsalz' (statement of 25 August 2003, in German) BfR statement · Source	Authoritative guidance n/a	One imported sample of black salt (kala namak) with hydrogen sulfide measured at about 200 mg per kg	n/a n/a n/a n/a · vs n/a	The BfR says the data do not allow a sure statement about the toxic relevance of hydrogen sulfide in black salt, but after weighing what it had, it concluded that normal use in Indian cooking poses no health risk. It found that the salt is used very sparingly (more gives an unwanted taste). For an invented 2 g of salt per meal the sample would give about 0.4 mg hydrogen sulfide (about 0.007 mg per kg body weight for 60 kg), and some of it escapes as gas during cooking. It notes that sulfides react with stomach acid to form hydrogen sulfide, that toxic effects are known mainly from breathing the gas, and that there is too little knowledge of effects after swallowing it, so it cannot say at what swallowed amount effects begin. It compared its figure with a US EPA reference dose (0.0031 mg per kg a day, built from a pig-feeding study) that it says is not suited to food assessment; the two are the same order of magnitude, but it noted the large safety factor and the occasional use. Opinion in 2003: no health hazard from normal use in Indian dishes Methods, limits and funding Outcomes: Whether hydrogen sulfide in black salt is a health risk when used as in Indian cooking Limitations: One sample, measured only roughly (semi-quantitatively) by a food institute; one opinion from 2003; fictional 2 g per meal assumption; the BfR says swallowed hydrogen sulfide data are lacking. It does not cover large amounts or other contaminants. Written in German. Funding and conflicts: Government risk-assessment body; no industry funding stated. Read: full-text
n/a 2023 Harvard T.H. Chan School of Public Health, The Nutrition Source: Salt and Sodium (read 2026-10-25) n/a · Source	Authoritative guidance n/a	n/a	n/a n/a n/a n/a · vs n/a	Says all salts are sodium chloride and the nutrient content varies minimally; less processed salts hold small amounts of minerals, not enough for substantial benefit; salts are chosen mainly for flavour. Its table gives about 2,300 mg sodium per teaspoon of fine iodized table salt and 1,150 to 2,200 mg per teaspoon of black salt. Says too much sodium can lead to high blood pressure, heart disease and stroke. Sodium in black salt overlaps with other salts Methods, limits and funding Outcomes: Salt and health; sodium in different salts Limitations: Teaspoon figures depend on grain size and brand. It does not discuss kala namak's sulfur compounds. Its mineral statement is made about sea and Himalayan salts, not tested on kala namak. Read: full-text
n/a 2023 NHS (UK): Salt in your diet (page last reviewed 17 April 2023; next review due 17 April 2026) n/a · Source	Authoritative guidance n/a	n/a	n/a n/a n/a n/a · vs n/a	Says too much salt can cause high blood pressure, which raises the risk of heart attacks and strokes. Adults should have no more than 6 g salt a day; the limit is lower for children by age and under 1 g for babies under 1 year, because their kidneys are not fully developed and cannot process much salt. Says some dissolvable tablets (painkillers, vitamins, prescription medicines) can be high in salt. Babies need very little salt Methods, limits and funding Outcomes: Salt limits by age Limitations: Review date has passed, so the page may have been updated. It does not mention black salt. Read: full-text
n/a 2026 WHO: Sodium reduction (fact sheet, 11 May 2026) n/a · Source	Authoritative guidance n/a	n/a	n/a n/a n/a n/a · vs n/a	Says almost all populations eat too much sodium (global mean 4,278 mg a day in 2021, about 11 g of salt). Says the main health effect of high-sodium diets is raised blood pressure, which raises the risk of heart disease, gastric cancer, obesity, osteoporosis, Meniere's disease and kidney disease. Recommends adults have under 2,000 mg sodium (under 5 g salt, about a teaspoon) a day, with the adult figure adjusted downward for ages 2 to 15, and says the advice does not cover babies up to 24 months. Says all salt that is consumed should be iodized. Sodium limits apply to any salt Methods, limits and funding Outcomes: Health effects of high sodium and WHO recommendations Limitations: A public-health fact sheet. It does not mention black salt. Read: full-text
n/a 2026 Wikipedia: Kala namak (read 2026-10-25; secondary source, used only to name claims, composition and the process) n/a · Source	Secondary source n/a	n/a	n/a n/a n/a n/a · vs n/a	Describes kala namak as a kiln-fired rock salt with a sulphurous smell used mainly in South Asia, also called Himalayan black salt, kala loon, sanchal and other names. Says it is mostly sodium chloride with traces of sodium sulphate, sodium bisulphate, sodium bisulphite, sodium sulphide, iron sulphide and hydrogen sulphide; iron sulphide gives the dark violet colour and sulphur compounds the smell. Says it is made by firing raw salt in a sealed jar with charcoal and herbal materials (such as harad, amla, bahera, babul bark) or natron, and that adding chemicals to pure salt before firing is now common. Says Ayurveda treats it as a cooling spice, laxative and digestive aid, and that goitre and hysteria uses are dubious. It also mentions an FDA warning to a Himalayan salt supplement maker; we did not confirm that. Background only Methods, limits and funding Outcomes: Names, production, composition, culinary and traditional uses Limitations: An encyclopedia page that anyone can edit. We did not check its own sources. Everything taken from it is marked as such. Read: full-text
n/a 2026 National Capital Poison Center: Poison Help (web page read 2026-10-25) n/a · Source	Authoritative guidance n/a	n/a	n/a n/a n/a n/a · vs n/a	Gives the US poison centre number 1-800-222-1222 (free, expert, confidential) and an online tool. Says to call 911 now if the person collapses, has a seizure, has trouble breathing or cannot be awakened. Where to get help in the US Methods, limits and funding Outcomes: How to get poison help Limitations: US service; other countries have their own poison centres and emergency numbers. Read: full-text

What we do not know yet

What the evidence supports: sodium raising blood pressure is well supported for any salt (high); everything specific to kala namak is a lab abstract, one 2003 opinion or tradition.
No trial of kala namak in people for any outcome.
The hydrogen sulfide result is one rough measurement of one sample from 2003, and swallowed-dose data are lacking.
No measured iodine or heavy-metal data for kala namak; microplastic and fluoride surveys are small.
No kala-namak-specific data on pregnancy, breastfeeding, children, allergy, sulfite sensitivity or medicine interactions. FDA, EFSA and Indian authorities were not checked.

How new research is added

New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating or safety wording. New publications never change ratings automatically.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Other 2

▼

Systolic blood pressure

Lowered in trials

The top number of a blood pressure reading, the pressure in the arteries when the heart beats.

High certainty

Results and what it means

Why it was measured

To see whether sodium changes pressure in the arteries.

Statistical vs. clinical meaning

Falls with less sodium of any kind. It was never measured for kala namak.

Safety implication

Cutting salt very sharply can cause symptoms of low blood pressure in some people, especially with kidney disease or blood-pressure medicines.

Study	Result	People	Product
²	Lower sodium cut systolic pressure by 4.26 mmHg (95% CI 3.62 to 4.89) and diastolic by 2.07 mmHg.	12,197 adults	Reduced versus usual sodium
¹¹	Each 100 mmol cut in 24-hour urinary sodium lowered systolic pressure by 6.81 mmHg (95% CI 4.96 to 8.66) in people on steady blood-pressure medicines.	2,885 treated people with high blood pressure	Reduced versus usual sodium

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▼

Albuminuria (protein in the urine)

Lowered in trials

Albumin, a blood protein, leaking into the urine. It is a sign of kidney damage.

High certainty

Results and what it means

Why it was measured

To see whether less salt eases strain on the kidneys in chronic kidney disease.

Statistical vs. clinical meaning

A lab marker, short term. The review says long-term benefit on kidney decline is not yet tested. It was not measured with kala namak.

Safety implication

The same review found more symptoms of low blood pressure with lower salt intake.

Study	Result	People	Product
⁷	Albuminuria fell by 36% (95% CI 26 to 44) in six trials, five in earlier-stage disease.	501 participants with chronic kidney disease	Lower versus usual salt intake

⁷

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 6

Kala namak is mostly salt: too much sodium raises blood pressure. Kala namak is mostly sodium chloride. Harvard lists black salt at 1,150 to 2,200 mg of sodium per teaspoon, against about 2,300 mg for fine iodized table salt, so it is not a low-sodium salt. WHO says the main health effect of high-sodium diets is raised blood pressure, which raises the risk of heart disease, stomach cancer and kidney disease, and says almost all populations eat too much sodium. No trial tested kala namak itself. Authoritative guidance ^{15 13 2}
A large amount of salt swallowed at once can poison. Salt poisoning (very high blood sodium) is documented after swallowing a large amount of salt. A systematic review of 15 case reports found half of the 14 cases with known outcomes were fatal, and 40% of patients were children. The authors of a 2025 adolescent case say 2 to 4 tablespoons taken rapidly can be lethal, depending on age and size. A newborn given formula made with too much powder reached a blood sodium of 174 mmol/L and had seizures and bleeding in the brain. This applies to any salt. It is a medical emergency: in the US call Poison Help on 1-800-222-1222, or your local emergency number. Case report ^{8 3 4 17}
Sulfur compounds and hydrogen sulfide: one old risk opinion, limited data. The smell of kala namak comes from sulfur compounds, with hydrogen sulfide the most prominent. In 2003 the German BfR looked at one imported sample with about 200 mg hydrogen sulfide per kg. It said the data did not allow a sure statement on the toxic relevance, but concluded that normal use in Indian cooking posed no health risk. It said cooks use the salt very sparingly and some of the gas escapes during cooking, and that there is too little knowledge of what swallowed hydrogen sulfide does. The opinion covers one sample and normal seasoning, not large amounts and not other brands. Authoritative guidance ^{12 16}
Babies and young children should have very little salt. The NHS says babies should not have much salt because their kidneys are not fully developed and cannot process it, and gives less than 1 g a day as the maximum for babies under 1 year. WHO's adult advice is adjusted downward for ages 2 to 15 and does not cover babies up to 24 months. The infant case above shows how salt mistakes can harm. No source read describes kala namak for children specifically. Authoritative guidance ^{14 15 4}
Do not count on it for iodine. No source we read measured iodine in kala namak. WHO says all salt that is consumed should be iodized. If you switch to kala namak for all your salt, you may lose the iodine that iodized table salt supplies; ask your clinician if you are pregnant, breastfeeding or have a thyroid condition. Authoritative guidance ^{15 16}
Products differ, and lab findings are few. Some kala namak is made the traditional way and some by adding chemicals to pure salt before firing (Wikipedia), so products are not the same. Lab surveys found microplastics in a black salt (157 particles per kg) and the highest fluoride of four salt types (77.5 ppm), which the authors called within prescribed limits. These come from a few samples, and the papers do not say if their black salt was kiln-fired kala namak. We found no lead or other heavy-metal testing of kala namak. Product analysis ^{16 6 10}

Side effects 4

Effect	How often	Severity and recovery	Evidence
Raised blood pressure with high sodium intake Applies to any salt, including kala namak.	Average effect: lower sodium cut systolic pressure by about 4 mmHg and diastolic by about 2 mmHg (133 trials).	moderate Falls again when sodium is reduced (trials).	Meta-analysis ^{2 15}
More heart disease and stroke with high salt intake Trial evidence on events is weaker than the evidence on blood pressure.	Cardiovascular disease RR 1.13 and stroke OR 1.34 for high versus lower salt intake in an umbrella review (observational data included).	serious Not applicable.	Systematic review ⁵
Salt poisoning (very high blood sodium) after a large single intake Documented for salt in general. No case with kala namak was found.	Rare. Of 14 case-report patients with known outcomes, 50% died.	life-threatening Can cause lasting brain injury; fast treatment may prevent it.	Case report ^{8 3 4}
Low blood pressure symptoms after a big salt cut in kidney disease A reason to ask your own kidney clinician before changing salt.	RR 6.70 (95% CI 2.40 to 18.69) in six trials of 678 people with chronic kidney disease; moderate certainty.	moderate Not described in the abstract.	Systematic review ⁷

Medicines and supplements 3

With	Why it matters	Importance	Evidence	What to do
Blood-pressure medicines (beta-blockers, renin-angiotensin system drugs and others) prescription	Sodium level changes how far blood pressure falls on medicines.	In 35 trials of people on steady blood-pressure medicines, each 100 mmol cut in 24-hour urinary sodium lowered systolic pressure by 6.81 mmHg, more with beta-blockers and renin-angiotensin-aldosterone system inhibitors. This is about sodium in general.	Meta-analysis Moderate certainty ¹¹	Tell your prescriber if you change how much salt you eat in a big way.
Dissolvable tablets (painkillers, vitamins, some prescribed medicines) prescription	Some dissolvable tablets contain a lot of salt, which adds to your total sodium.	The NHS notes some dissolvable tablets may be high in salt. This is general advice, not about kala namak.	Authoritative guidance Low certainty ¹⁴	Speak to your doctor before changing medicines.
No kala-namak-specific medicine interaction found other	Not described.	The sources read describe none. Not described is not proof of none.	Insufficient Not enough evidence ¹²	Ask a pharmacist if you take regular medicines and plan to use a lot of any salt.

Who should check first 4

Situation	Advice	Evidence
Babies and young children	Babies should not have much salt (NHS). Ask a doctor or health visitor before giving any salt to a child.	Authoritative guidance ^{14 15}
High blood pressure, heart disease or kidney disease	Treat kala namak like any other salt, and ask your clinician about your own sodium limit. In kidney disease, trials show cutting salt lowers blood pressure and urine protein but can cause low-blood-pressure symptoms.	Systematic review ^{7 15}
Pregnancy and breastfeeding	No source read describes kala namak in pregnancy or breastfeeding. General salt limits apply, and iodine needs are not shown to be met by this salt. Ask your midwife or doctor.	Insufficient ¹⁵
Large amounts or swallowing a lot at once	Dangerous with any salt. Get emergency help; do not try to treat it at home.	Case report ^{8 17}

Overdose, product quality and regulators

Summary. Salt is toxic in large amounts. The review of 15 case reports found half of known outcomes fatal. For kala namak's sulfur compounds, the BfR says there is too little knowledge of swallowed hydrogen sulfide to give a safe amount.

Animal. The BfR statement cites animal data on breathed hydrogen sulfide and a pig study used for a US reference dose, which it says is not suited to assessing foods. Not reviewed further.

Human doses studied. No trial of kala namak in people. The BfR used an invented 2 g salt per meal for its estimate.

High dose or long term signals. Long-term high sodium raises blood pressure (WHO). No long-term kala namak data.

Overdose response. Treat as an emergency. In the US call Poison Help on 1-800-222-1222; call 911 if the person collapses, has a seizure, has trouble breathing or cannot be awakened. Elsewhere call your local emergency number or poison centre.

Genotoxicity. Not read.

Specialty salts are not free of contaminants, and kala namak has little testing. Two lab surveys included a black salt; neither paper says whether it was kiln-fired kala namak.

Hydrogen sulfide. The BfR measured about 200 mg per kg (rough method) in one imported sample in 2003 and judged normal Indian-cooking use to be no health risk, while noting data gaps. ¹²

Microplastics. In an Australian survey of commercial salts, black salt had 157.41 (SD 23.13) particles per kg, second to coarse Himalayan pink salt (174.04). The average was 85.19 per kg. Health effects are unknown. ⁶

Fluoride. Black salt had the highest fluoride of four salt types, 77.5 (SD 19.9) ppm, against 12.5 ppm for iodized salt. The authors say all were well within prescribed limits. Two brands per type. ¹⁰

Heavy metals, adulteration. No lead, arsenic or similar testing of kala namak was found in the sources read. Wikipedia says some products are made by adding chemicals to pure salt before firing, so makeup varies. ¹⁶

Body	Action	Date
Bundesinstitut fuer Risikobewertung (BfR), Germany (Germany)	Statement of 25 August 2003 on hydrogen sulfide in black salt: no sure toxicological statement possible, but no health risk to consumers from normal use in Indian cooking. source	2003-08-25
World Health Organization (WHO) (International)	Says high sodium raises blood pressure and the risk of heart disease, stomach cancer, kidney disease and other problems; recommends adults have under 2,000 mg sodium (under 5 g salt) a day, adjusted down for children 2 to 15; all consumed salt should be iodized. source	2026-05-11
NHS (United Kingdom) (United Kingdom)	Says too much salt can cause high blood pressure; adults no more than 6 g a day; less than 1 g for babies under 1 year. source	2023-04-17

When to get medical help

Anyone who has swallowed a large amount of salt, or a baby given formula mixed with too much powder, who becomes very sleepy, stops feeding, vomits repeatedly or has a seizure: get emergency help now. In the US call Poison Help on 1-800-222-1222; call 911 if the person collapses, has a seizure, has trouble breathing or cannot be awakened.
Call your local emergency number if you are not in the US. Do not wait for symptoms to settle.
If you are on blood-pressure or kidney treatment and feel faint or dizzy after a big change in how much salt you eat, tell your clinician.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What is black salt (kala namak)?

It is a South Asian rock salt that is fired in a kiln, which gives it a sulfur, egg-like smell. It is mostly sodium chloride with traces of sulfur compounds and iron sulfide. Wikipedia says it is traditionally fired in a sealed jar with charcoal and herbal materials, and that adding chemicals to pure salt before firing is now common.

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Why does it smell like eggs?

Sulfur compounds cause the smell, and hydrogen sulfide is the most prominent. Cooks use it sparingly, and it is popular on chutneys, raita, chaat masala and in vegan egg-style tofu dishes.

^{16 12}

Is black salt healthier than table salt?

We found no proof of that. It is mostly sodium chloride. Harvard lists black salt at 1,150 to 2,200 mg of sodium per teaspoon against about 2,300 for fine iodized table salt, a range that overlaps. One lab abstract says it has less sodium than sea and pink salt but gives no figures. Harvard says the trace minerals in specialty salts are too small to give substantial benefit.

^{13 1}

Is the hydrogen sulfide in it harmful?

A 2003 German risk assessment of one imported sample (about 200 mg hydrogen sulfide per kg) concluded that normal use in Indian cooking posed no health risk. It also said there is too little knowledge of what swallowed hydrogen sulfide does, so it could not give a sure toxic assessment. It covers normal seasoning, not large amounts.

¹²

Does black salt help digestion or constipation?

Ayurveda and folk use describe it as a digestive aid, laxative and cooling spice. We found no human or animal study testing these uses, so the evidence is insufficient.

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Does it contain iodine?

We found no source that measured iodine in kala namak. WHO says all salt that is consumed should be iodized. Ask your clinician if you rely on salt for iodine, for example in pregnancy.

^{15 16}

Is black salt safe if I have high blood pressure or kidney disease?

Treat it like any other salt. Less sodium lowers blood pressure in trials, including in people on medicines. In kidney disease, cutting salt lowers blood pressure and urine protein but can cause symptoms of low blood pressure, so the right level is for your own clinician.

^{2 11 7}

Can salt be poisonous?

Yes, in large amounts. A review of 15 case reports found half of the cases with known outcomes were fatal. A newborn given formula with too much powder had seizures and bleeding in the brain. The authors of a teenager's case say 2 to 4 tablespoons taken rapidly can be lethal, depending on age and size. Call your poison centre or emergency number (in the US, 1-800-222-1222).

^{8 4 3 17}

Is it safe in pregnancy, or for babies and children?

No source we read describes kala namak in pregnancy or for children. The NHS says babies should not have much salt because their kidneys cannot process it, with less than 1 g a day as the limit under 1 year. Ask your doctor or midwife.

^{14 15}

Does it contain microplastics, fluoride or heavy metals?

A lab survey of Australian salts found microplastics in a black salt (157 particles per kg), and a small Indian survey found the highest fluoride in black salt (77.5 ppm), which the authors called within prescribed limits. We found no heavy-metal testing of kala namak. Samples were few and the papers do not say if they were kiln-fired kala namak.

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Is it the same as Himalayan pink salt?

No. Pink salt is an unfired rock salt coloured by a little iron oxide, while kala namak is fired and has sulfur compounds. 'Himalayan black salt' is a name used for kala namak, and its powder can look pink, so the two are easy to mix up.

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Does black salt detox the body or cure anything?

No source we read shows that. Traditional uses are described, but they have not been tested in people. Salt is not a remedy, and WHO says high-sodium diets raise blood pressure and the risk of heart and kidney disease.

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We searched PubMed and Europe PMC for kala namak and black salt, read the abstracts of the PubMed papers, read the German BfR statement in full, and read the WHO, NHS, Harvard, Poison Help and Wikipedia pages. We checked PubChem for the chemical names. Certainty ratings are the compiler's own reading. Where the sodium and blood pressure evidence is rated high, that is for sodium in general, not for kala namak. Lab surveys use a few samples and may not describe the kiln-fired product. No study is cited that we could not verify.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. This page is information, not a recommendation to buy or use any salt.

Sources 17

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

Chander V, Tewari D, Negi V, Singh R. Structural characterization of Himalayan black rock salt by SEM, XRD and in-vitro antioxidant activity. Science of the Total Environment. 2020. PMID 32798866. DOI 10.1016/j.scitotenv.2020.141269. (abstract)
Huang L, Trieu K, Yoshimura S, et al. Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials. BMJ. 2020. PMID 32094151. DOI 10.1136/bmj.m315. (abstract)
Hull A, Reddy A. Salty Despair: An Adolescent's Suicide Attempt through Salt Overdose. Psychopharmacology Bulletin. 2025. PMID 39744409. DOI 10.64719/pb.4515. (abstract)
Kakoo Brioso E, Moscoso J, Vieira F, et al. Salt Poisoning Due to Inadequate Infant Formula Preparation: A Rare Cause of Hypernatremia and Massive Cerebral Hemorrhage in a Newborn. Cureus. 2022. PMID 36721612. DOI 10.7759/cureus.33045. (abstract)
Kong F, Liu Q, Zhou Q, et al. Dietary salt intake and cardiovascular outcomes: an umbrella review of meta-analyses and dose-response evidence. Annals of Medicine. 2025. PMID 41243115. DOI 10.1080/07853890.2025.2582065. (abstract)
Kuttykattil A, Raju S, Vanka KS, et al. Consuming microplastics? Investigation of commercial salts as a source of microplastics (MPs) in diet. Environmental Science and Pollution Research. 2023. PMID 35907067. DOI 10.1007/s11356-022-22101-0. (abstract)
McMahon EJ, Campbell KL, Bauer JD, et al. Altered dietary salt intake for people with chronic kidney disease (Cochrane review). Cochrane Database of Systematic Reviews. 2021. PMID 34164803. DOI 10.1002/14651858.CD010070.pub3. (abstract)
Metheny NA, Krieger MM. Salt Toxicity: A Systematic Review and Case Reports. Journal of Emergency Nursing. 2020. PMID 32340735. DOI 10.1016/j.jen.2020.02.011. (abstract)
Mooss NS. Salt in ayurveda I. Ancient Science of Life. 1987. PMID 22557573. (abstract)
Pai A, Ramanarayanan V, Rajeev K. Analysis of Fluoride Content of Different Types of Salts Used in the Indian Diet: An In Vitro Study. Cureus. 2024. PMID 39246882. DOI 10.7759/cureus.66418. (abstract)
Song J, Chen L, Xiong H, et al. Blood Pressure-Lowering Medications, Sodium Reduction, and Blood Pressure. Hypertension. 2024. PMID 39236753. DOI 10.1161/HYPERTENSIONAHA.124.23382. (abstract)
n/a. Bundesinstitut fuer Risikobewertung (BfR, German Federal Institute for Risk Assessment): Vorkommen von Schwefelwasserstoff in 'Schwarzsalz' (statement of 25 August 2003, in German). BfR statement. 2003. (full-text)
n/a. Harvard T.H. Chan School of Public Health, The Nutrition Source: Salt and Sodium (read 2026-10-25). n/a. 2023. (full-text)
n/a. NHS (UK): Salt in your diet (page last reviewed 17 April 2023; next review due 17 April 2026). n/a. 2023. (full-text)
n/a. WHO: Sodium reduction (fact sheet, 11 May 2026). n/a. 2026. (full-text)
n/a. Wikipedia: Kala namak (read 2026-10-25; secondary source, used only to name claims, composition and the process). n/a. 2026. (full-text)
n/a. National Capital Poison Center: Poison Help (web page read 2026-10-25). n/a. 2026. (full-text)

Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.