Corn silk (Zea mays): Uses, Evidence and Safety
Corn silk (Zea mays styles and stigmas): traditional urinary and diuretic use, thin trial evidence on blood pressure and blood sugar, and cautions for kidney disease, water pills and pregnancy.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read herb safety and interactions before you use anything on this page.
What is Corn silk good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Blood pressure (added to medicines)
Preliminary or mixedA 2019 review of 5 small trials found limited evidence that corn silk tea added to blood pressure drugs might lower blood pressure more than the drugs alone.
Supplements: Not shown to replace blood pressure medicine; evidence is limited and low quality.
Blood sugar after meals
Preliminary or mixedTwo small 2025 crossover trials of a mulberry leaf plus corn silk extract saw smaller glucose rises after a meal in some people. Animal results are inconsistent.
Supplements: Not established; do not change diabetes treatment.
Diuretic (urine-increasing) effect
Lab or animal research onlyCorn silk is traditionally described as a diuretic. In water-loaded rats a water extract increased urine at a high dose.
Supplements: No human evidence found in the sources read.
Urinary tract complaints (traditional use)
Not enough evidenceTeas and supplements are traditionally used for urinary problems. The EU herbal committee is still drafting its monograph.
Supplements: Proper evidence not found in the sources we read.
Fatigue and low mood (claimed uses)
Not enough evidenceA 2012 review lists anti-fatigue and antidepressant uses as claims from reports.
Supplements: Proper evidence not found in the sources we read.
Antioxidant activity (laboratory)
Lab or animal research onlyThe 2012 review describes antioxidant properties linked to flavonoids and terpenoids.
Supplements: No human evidence found in the sources read.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Body systems (2)
- Kidney & UrinaryDocumented risk
Traditionally used for urinary complaints and described as a diuretic. Rat findings on potassium loss and kidney filtering mean people with kidney disease should ask first; no human study was found.
- Urinary SystemDocumented risk
Traditionally used for urinary complaints; the diuretic effect is shown only in rats. The EU review is still a draft.
Body parts (1)
- KidneysDocumented risk
In rats a high dose lowered a kidney filtering measure and raised potassium loss. Human relevance unknown.
Root causes (1)
- Medication Side EffectsDocumented risk
No human interaction study was found, but diuretic and potassium findings in rats and blood sugar findings in small trials are reasons to ask a pharmacist if you take water pills or heart or diabetes medicines.
Documented risks and interactions (3)
- Potassium loss and kidney filtering (rat findings). In rats, a water extract increased potassium excretion and lowered a measure of kidney filtering at a high dose.
- Interaction with diuretics, heart and diabetes medicines (theoretical). No human interaction study was found; the diuretic, potassium and blood sugar findings are a reason to ask a pharmacist.
- Pregnancy. In pregnant rats a standardized extract caused no malformations, but the highest dose increased losses before implantation. No human data were found.
Safety first: who should check before using corn silk
Corn silk is sold as a tea, extract and capsule and is traditionally taken as a "water" herb. The sources we read describe it as a diuretic (a substance that makes the body pass more urine). [1][2] In rats, a water extract raised urine volume and potassium loss at high doses, and also lowered a measure of kidney filtering. [2] We found no human study that measured these effects, so nobody can say how they apply to people. If you have kidney disease, take water pills (diuretics), heart or blood pressure medicines, or have diabetes, ask a doctor or pharmacist before using corn silk. See how herb and medicine interactions work and herbs and kidney disease. Proper evidence of safety in pregnancy, breastfeeding or children was not found in the sources we read.Overview
Corn silk is the soft, thread-like styles and stigmas of the female flowers of maize, Zea mays L., a grass in the family Poaceae. GBIF lists Zea mays L. as the accepted name. [3] In herbal medicine the material is called Stigma maydis or Maydis stigma. [1][4] The native range was not stated in the sources we read. This page covers the herb as a medicine or supplement; for the tea see corn silk and barley teas. Fresh silk from sweetcorn, dried silk, teas, extracts and capsules all appear under this name.Traditional use (not proof of benefit)
A 2012 review says corn silk has been used traditionally by Chinese and Native American peoples for many diseases, and also in places such as Turkey, the United States and France. [1] Teas and supplements are used for urinary-related problems, and the review lists claimed uses as a diuretic, for lowering blood sugar, as an antidepressant and for fatigue. [1] The European Medicines Agency (EMA) places corn silk in the therapeutic area of urinary tract and genital disorders. [4] These are traditions and claims, not trial results.What research shows
| Use | What the sources found | Strength of evidence | Form and population |
|---|---|---|---|
| High blood pressure | A 2019 review of 5 randomized trials (567 people) found that, because most trials were poorly conducted, limited evidence suggested corn silk tea added to blood pressure drugs might lower blood pressure more than the drugs alone. [5] | Insufficient evidence (poor-quality trials) | Tea added to usual medicines; people with hypertension |
| Safety in those trials | The same review found no evidence that adding the tea caused fewer side effects than drugs alone. [5] | Insufficient evidence | Same trials |
| Blood sugar after meals | Two small 2025 crossover trials tested a combined mulberry leaf and corn silk extract, one in 28 adults with type 2 diabetes (lower peak glucose after bread versus water) and one in 11 people with prediabetes (no difference overall; a drop only in an overweight subgroup). [6][7] | Insufficient evidence (small, mixed, two herbs combined) | Combination extract with a meal; adults |
| Blood sugar in diabetic animals | A 2026 meta-analysis of 8 animal studies found corn silk raised insulin but was not better than control drugs at lowering blood glucose, and results varied a lot. [8] | Animal findings only | Animal models |
| Diuretic effect | In water-loaded rats a water extract increased urine at 500 mg/kg and potassium loss at 350 and 500 mg/kg. [2] | Animal findings only | Rats |
| Urinary tract complaints and kidney stones | Proper evidence not found in the sources we read. The EU monograph is still a draft. [4] | Insufficient evidence |
Forms and why the form matters
Hypertension trials used corn silk tea, as an add-on to medicines. [5] The glucose trials used a mulberry leaf plus corn silk extract mixed into foods, so the results cannot be assigned to corn silk alone. [6][7] A rat study used a standardized dry extract made with 41% ethanol. [9] Teas, home-dried silk and concentrated extracts differ, and the sources we read do not compare them. Amounts are a decision for a clinician or pharmacist, not this page.Safety in more detail
- Side effects in people: Proper evidence not found in the sources we read for a list of side effects. The review of hypertension trials gave no good information on harms. [5]
- Medicines: no human interaction study was found. Because of the diuretic and potassium findings in rats [2], ask about water pills, heart medicines and blood pressure medicines. Because small trials looked at blood sugar [6][7], people on diabetes medicines should ask too.
- Kidney: in rats the extract lowered creatinine clearance (a kidney filtering measure) at a high dose. [2] The meaning for people is unknown. A 2012 review says toxicology studies are covered, but we could read only its abstract. [1]
- Pregnancy: in pregnant rats a standardized extract caused no maternal or fetal toxicity or malformations, but the highest dose (1200 mg/kg) increased losses before implantation. [9] No human data were found, so ask a midwife or doctor.
- Breastfeeding and children: Proper evidence not found in the sources we read.
- Allergy: the sources we read did not report on allergy to corn silk. People with known corn or grass-pollen allergy should ask a clinician.
- Liver: we did not find a liver safety statement in the sources we read.
- Quality: the sources we read do not discuss contamination or adulteration. See quality testing and certifications.
Official statements
- EMA (EU), page read 2026: the herbal committee's work on corn silk (Maydis stigma) is listed as "draft under discussion"; a draft monograph and assessment report were published for consultation on 15 October 2025, and the consultation closed on 15 January 2026. We could not read the draft contents. [4]
- NCCIH (US): no page for corn silk was found (the address returned "not found"). [10]
Related pages
Frequently asked questions
Is corn silk a diuretic?
It is described that way traditionally, and a rat study found more urine and potassium loss at high doses. [1][2] We found no human study measuring it.
Does corn silk lower blood pressure?
Only add-on trials exist. A 2019 review found limited, poor-quality evidence that corn silk tea plus medicines might help more than medicines alone. [5]
Can corn silk help with diabetes?
Two small 2025 trials used a mulberry leaf and corn silk combination and saw smaller glucose rises after a meal in some people. [6][7] Animal results are inconsistent. [8] Do not change diabetes treatment without your clinician.
Is corn silk safe in pregnancy?
Human data were not found. In pregnant rats a standardized extract caused no malformations, but the highest dose increased early pregnancy losses. [9]
Does corn silk treat kidney stones or bladder infections?
Proper evidence not found in the sources we read. The EU review of corn silk is still in draft. [4]
References
- Hasanudin K, Hashim P, Mustafa S. Corn silk (Stigma maydis) in healthcare: a phytochemical and pharmacological review. Molecules, 2012. PMID 22890173. Read 2026-10-23 (abstract, via Europe PMC).
- Velazquez DV, et al. Zea mays L. extracts modify glomerular function and potassium urinary excretion in conscious rats. Phytomedicine, 2005. PMID 15957371. Read 2026-10-23 (abstract, via Europe PMC).
- GBIF Secretariat. GBIF species match for Zea mays: accepted name Zea mays L., family Poaceae. Read 2026-10-23.
- European Medicines Agency, HMPC. Maydis stigma (corn silk): herbal medicinal product, status page. Read 2026-10-23.
- Shi S, et al. Corn silk tea for hypertension: a systematic review and meta-analysis of randomized controlled trials. Evid Based Complement Alternat Med, 2019. PMID 30792743. Read 2026-10-23 (abstract, via Europe PMC).
- Postprandial glycemic effects of lactose-hydrolyzed milk supplemented with mulberry leaf and corn silk extracts in adults with type 2 diabetes: a randomized crossover trial. 2025. PMID 40187731. Read 2026-10-23 (abstract, via Europe PMC).
- Effects of mulberry leaf and corn silk extracts against alpha-amylase and alpha-glucosidase in vitro and on postprandial glucose in prediabetic individuals: a randomized crossover trial. 2025. PMID 41228506. Read 2026-10-23 (abstract, via Europe PMC).
- Anti-diabetic potential of corn (Zea mays L.) silk: a systematic review and meta-analysis of preclinical studies. 2026. PMID 41815193. Read 2026-10-23 (abstract, via Europe PMC).
- Toxicological assessment of a standardized dry extract of Zea mays L. stigmas during gestation in Wistar rats. 2025. PMID 40984809. Read 2026-10-23 (abstract, via Europe PMC).
- National Center for Complementary and Integrative Health (NIH). Address nccih.nih.gov/health/corn-silk returned "not found". Tried 2026-10-23.