What is it?
Despite serious safety concerns, pennyroyal is used for colds, pneumonia, and other breathing problems. It is also used for stomach pains, gas, intestinal disorders, and liver and gallbladder problems.
Women use it to start or regulate their menstrual periods, or to cause an abortion.
Pennyroyal is also used to control muscle spasms, cause sweating, and increase urine production.
Some people use it as a stimulant and to counteract weakness.
Pennyroyal is applied to the skin to kill germs, keep insects away, and treat skin diseases. It is also used topically for gout, venomous bites, and mouth sores; and as a flea-killing bath.
In foods, pennyroyal is used for flavoring.
In manufacturing, pennyroyal oil is used as a dog and cat flea repellent; and as a fragrance for detergents, perfumes, and soaps.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for PENNYROYAL are as follows:
Insufficient evidence to rate effectiveness for...
- Causing abortion. The large doses needed to cause an abortion can kill the mother or cause her irreversible kidney and liver damage.
- Reducing spasms.
- Intestinal gas.
- Stomach pains.
- Fluid retention.
- Killing germs.
- Skin diseases.
- Other conditions.
How does it work?
Are there safety concerns?
Repeated use of an alcoholic pennyroyal leaf extract over a period of 2 weeks has been linked to a death.
Not enough is known about the safety of using pennyroyal leaf as a tea.
Special precautions & warnings:Pennyroyal is LIKELY UNSAFE for anyone to use, but it is especially unsafe for children and people with the following conditions.
Pregnancy and breast-feeding: If you are pregnant or breast-feeding, it is LIKELY UNSAFE to take pennyroyal by mouth or apply it to your skin. There is some evidence that pennyroyal oil can cause abortions by causing the uterus to contract. But the dose needed for this effect could kill the mother or cause her life-long kidney and liver damage.
Pennyroyal leaf tea seems to be able to start menstruation, which could also threaten a pregnancy.
Children: It is LIKELY UNSAFE to give children pennyroyal by mouth. Two infants developed serious liver and nervous system injuries after taking pennyroyal, and one infant died.
Kidney disease: The oil in pennyroyal can irritate the kidney and make existing kidney disease worse.
Liver disease: The oil in pennyroyal can cause liver damage and might make existing liver disease worse.
Are there interactions with medications?
- It is not known if this product interacts with any medicines.
Before taking this product, talk with your health professional if you take any medications.
Are there interactions with herbs and supplements?
- Pennyroyal might reduce the absorption of iron supplements.
Are there interactions with foods?
- Pennyroyal appears to reduce the absorption of iron from foods.
What dose is used?
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
- Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. Br.J Nutr 1999;81:289-295. View abstract.
- Sullivan JB Jr, Rumack BH, Thomas H Jr, et al. Pennyroyal oil poisoning and hepatotoxicity. JAMA 1979;242:2873-4. View abstract.
- 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;124:726-34. View abstract.
- Sudekum M, Poppenga RH, Raju N, Braselton WE Jr. Pennyroyal oil toxicosis in a dog. J Am Vet Med Assoc 1992;200:817-8.. View abstract.
- Bakerink JA, Gospe SM Jr, Dimand RJ, Eldridge MW. Multiple organ failure after ingestion of pennyroyal oil from herbal tea in two infants. Pediatrics 1996;98:944-7. View abstract.
- Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
- The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
- Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
- Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.