Pennyroyal Tea (Dangers): What to Know Before Drinking
Pennyroyal tea is not recommended. Pulegone in pennyroyal has caused liver failure and deaths, including infants and women trying to end a pregnancy. A safety profile, with no brewing advice.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read herbal tea and extract safety before you use anything on this page.
Check before you drink: pennyroyal tea is not recommended for anyone. Memorial Sloan Kettering Cancer Center (MSK) calls pennyroyal an extremely toxic herb that has caused multiple organ failure and death, and says it must not be taken in pregnancy or while breastfeeding. [1] NIH's LiverTox says pennyroyal oil taken by mouth is highly toxic and has been linked to toxic liver injury and death. [2] Two infants developed liver and brain injury after mint teas that contained pennyroyal; one died. [3] If someone may have swallowed pennyroyal, call a poison center (US: 1-800-222-1222) or your local emergency number right away.
This page is a safety profile. It does not give brewing directions or amounts, on purpose. For the plant profile see the pennyroyal herb page.
What pennyroyal is
"Pennyroyal" is a common name for two different mint-family plants (Lamiaceae): European pennyroyal, Mentha pulegium L., and American pennyroyal, Hedeoma pulegioides (L.) Pers. [4] MSK covers both. [1] The part used is the above-ground plant (leaves and tops). It is a herbal tea (tisane), not a true tea, and a label that says only "pennyroyal" does not say which plant is inside. The main toxic compound is pulegone, which the liver turns into menthofuran and other harmful products. [1][5] MSK says oil from European pennyroyal is about 80 to 90 percent pulegone and American pennyroyal oil about 16 to 30 percent. [1]A second danger is a mix-up: infants were poisoned by home-brewed "mint" teas from plants that contained pennyroyal oil. [3] Never make tea from plants you picked and did not identify with certainty.
Taste, caffeine and how to brew
| Question | What sources say |
|---|---|
| Taste | Not described in the sources we read. |
| Caffeine | Not found in the sources we read; pennyroyal is not the tea plant. |
| Water temperature, steeping time, amount per cup | Not given, on purpose. This herb is not recommended. |
| Cold brew / iced | Not given, on purpose. |
What research found about the tea itself
There are poisoning reports and lab research, but no human trial showing a benefit. MSK found no scientific evidence for the folk uses it lists. [1]| Question | What the source found | Strength of evidence | Form and who was studied |
|---|---|---|---|
| Ending a pregnancy or bringing on a period | MSK says there is no scientific evidence it works for this and reports deaths in young women who took the oil to end a pregnancy. [1] A 2023 review names pennyroyal among herbal abortifacients with significant illness and death. [6] | No good evidence of benefit; evidence of harm | Oil and herb; women |
| Colic or minor ailments in babies | Hepatic and neurologic injury in two infants after mint tea containing pennyroyal oil: one died of liver failure with brain swelling, the other developed severe epilepsy. [3] | Evidence of harm (case report) | Home-brewed tea, infants |
| Adults drinking pennyroyal tea | MSK describes a 76-year-old woman with acute liver failure possibly linked to pennyroyal tea taken with other medicines. [1] | Evidence of harm (single case) | Tea, one adult |
| Colds, flu, headache, insect repellent | MSK states no scientific evidence for these uses. [1] | No good evidence of benefit | Not applicable |
| Trials of the tea itself | Proper evidence not found for trials of the tea itself. | Insufficient evidence | None |
Limits: nearly all the evidence is case reports and case series. They cannot say how common harm is. A 1996 review of 18 earlier cases found moderate to severe toxicity in people exposed to at least 10 mL of the oil; this shows where harm was seen, not a safe level. [7] The sources we read give no safe amount of tea.
Check before you drink
- Do not use it. No form has been shown to be safe in the sources we read.
- Liver: pulegone is turned into harmful products that use up glutathione, a liver protector; LiverTox lists the harm as toxic liver injury and death. [1][2][5] See liver and kidney cautions.
- Other organs: MSK lists liver and kidney failure, low blood sugar, clotting problems and seizures in published cases. [1] Poison center pages add stomach upset early on, with bleeding and multiple organ failure later. [5][8]
- Pregnancy and breastfeeding: MSK says it is contraindicated in both, because it can cause miscarriage and other toxic effects. [1] If you are worried about a pregnancy, a clinician can talk through safe options. See pregnancy teas to ask about.
- Babies and children: deaths and brain injury were reported in infants. [3] The poison center advises never giving herbs or teas to children without checking with a clinician. [8] See herbal tea for babies and children.
- Medicines and iron: MSK says the liver enzyme CYP2E1 is the main one that breaks down pulegone, and that pennyroyal may interact with medicines handled by CYP450 enzymes. [1] It also says the plant's flavonoids may cut iron absorption by 50 percent or more with iron supplements. [1] See herbal tea medicine interactions.
- Allergy, surgery, metals, pesticides: not described in the sources we read.
- Treatment: the National Capital Poison Center says there is no antidote and that an emergency room visit will likely be needed. [8] The Tennessee poison center says care is supportive, and that N-acetylcysteine may be considered early. [5]
- Emergency: call a poison center (US: 1-800-222-1222) or your local emergency number. See poisoning: what to do first.
Tea, capsule or extract?
The essential oil is the most concentrated form and is linked to most severe poisonings, but tea has also caused harm. [1][3] See tea vs tincture vs capsule and the pennyroyal herb page.Buying and storing
We do not recommend buying pennyroyal tea. Check blends and "mint" teas for pennyroyal on the label; see reading an herbal tea or tincture label. Keep any pennyroyal product away from children and pets.Related pages
What research found and what to check: Pennyroyal Tea (Dangers)
Findings about drinking the tea itself, kept apart from capsules, extracts and concentrated supplements. Each card says what was studied, in whom, and how strong the evidence is.
Pennyroyal tea for colds, periods or other uses
Not enough evidenceMSK found no scientific evidence for uses such as colds, flu, headache, menstrual problems or insect repellent. Proper evidence not found for trials of the tea itself.
Supplements: No good evidence of benefit.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Body systems (4)
- Hepatic / Liver SystemDocumented risk
Pennyroyal's pulegone causes toxic liver injury and deaths.
- Reproductive HealthDocumented risk
MSK says it can cause miscarriage; deaths reported in women using the oil to end a pregnancy.
- Kidney & UrinaryDocumented risk
MSK lists kidney failure in published cases.
- Nervous SystemDocumented risk
Seizures, brain swelling and severe epilepsy have been reported.
Body parts (3)
- LiverDocumented risk
Liver failure is the best-documented harm, including in infants.
- KidneysDocumented risk
MSK lists kidney toxicity in published cases.
- Reproductive OrgansDocumented risk
Contraindicated in pregnancy per MSK.
Root causes (1)
- Medication Side EffectsDocumented risk
MSK describes possible CYP450-related interaction and a possible case with other medicines.
Conditions & symptoms (2)
- Liver Failure, AcuteDocumented risk
Acute liver failure and death have been reported after pennyroyal oil and tea.
- SeizuresDocumented risk
Seizures and severe epilepsy were reported in poisoning cases.
Documented risks and interactions (7)
- Liver failure from pulegone. Pulegone, the main toxic compound, is turned by the liver into harmful products that use up glutathione. Pennyroyal oil by mouth has caused toxic liver injury and death; tea has also been linked to harm.
- Deaths and organ failure in infants given pennyroyal in tea. Two infants given mint teas that contained pennyroyal developed liver and brain injury; one died of liver failure with brain swelling and the other had severe epilepsy.
- Pregnancy, miscarriage and attempts to end a pregnancy. MSK says it is contraindicated in pregnancy and breastfeeding, and that young women have died after taking the oil to end a pregnancy. No scientific evidence it works for this.
- Poison center guidance: emergency steps. If someone may have swallowed pennyroyal, call a poison center (US: 1-800-222-1222) or local emergency number. The National Capital Poison Center says there is no antidote; care is supportive and early hospital treatment may include N-acetylcysteine.
- Kidney, blood sugar, clotting and seizures. MSK lists liver and kidney failure, low blood sugar, clotting problems and seizures in published cases.
- Medicines and iron. MSK says pulegone is broken down mainly by CYP2E1 and describes a possible case of liver failure with pennyroyal tea and other medicines. It also says the plant's flavonoids may cut iron absorption by 50 percent or more with iron supplements.
- Look-alike and mix-up: 'mint' teas. Infants were poisoned by home-brewed mint teas from plants that contained pennyroyal oil. American and European pennyroyal are different plants with different pulegone levels.
Frequently asked questions
Is pennyroyal tea safe?
No. MSK calls pennyroyal extremely toxic, and LiverTox links the oil to severe liver injury and death. [1][2] Infants have been seriously harmed by teas containing it. [3]
Can pennyroyal tea end a pregnancy?
MSK found no scientific evidence that it works for this, and reports deaths in young women who tried. [1] A 2023 review lists it among herbal abortifacients with significant illness and death. [6] A clinician can talk through safe options.
Is American pennyroyal the same as European pennyroyal?
No. They are different plants (Hedeoma pulegioides and Mentha pulegium) with the same common name and different pulegone levels. [1][4]
What should I do if someone drank pennyroyal tea?
Call a poison center (US: 1-800-222-1222) or your local emergency number right away. [8]
Does pennyroyal tea help with colds or period problems?
MSK found no scientific evidence for these uses. [1]
References
- Memorial Sloan Kettering Cancer Center. Pennyroyal. Page last updated January 12, 2022. Read 2026-10-23.
- National Institute of Diabetes and Digestive and Kidney Diseases. Pennyroyal Oil (LiverTox). 2012. PubMed 31643984 (Bookshelf NBK548673); only the short summary abstract was read through Europe PMC. Read 2026-10-23.
- Bakerink JA, Gospe SM, Dimand RJ, Eldridge MW. Multiple organ failure after ingestion of pennyroyal oil from herbal tea in two infants. Pediatrics. 1996. PubMed 8909490. Abstract read through Europe PMC. Read 2026-10-23.
- GBIF Secretariat. GBIF Backbone Taxonomy species match: Mentha pulegium L. (key 2927189) and Hedeoma pulegioides (L.) Pers. (key 2926704). Read 2026-10-23.
- Middle Tennessee Poison Center (Vanderbilt University Medical Center). What is the toxicity of pennyroyal? (Toxicology Question of the Week, Aug 19, 2002). Read 2026-10-23.
- Feng C, Fay KE, Burns MM. Toxicities of herbal abortifacients. Am J Emerg Med. 2023. PubMed 36924751. Abstract read through Europe PMC. Read 2026-10-23.
- Anderson IB, Mullen WH, Meeker JE, et al. Pennyroyal toxicity: measurement of toxic metabolite levels in two cases and review of the literature. Ann Intern Med. 1996. PubMed 8633832. Abstract read through Europe PMC. Read 2026-10-23.
- National Capital Poison Center. Pennyroyal oil. No publication date shown. Read 2026-10-23.