Pennyroyal: MedlinePlus Supplements

T What is it?
P Pennyroyal is a plant. The oil and leaves are used to make medicine. Throughout history, both American pennyroyal and European pennyroyal have been used interchangeably as a source of oil.
P 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.
P Women use it to start or regulate their menstrual periods, or to cause an abortion.
P Pennyroyal is also used to control muscle spasms, cause sweating, and increase urine production.
P Some people use it as a stimulant and to counteract weakness.
P 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.
P In foods, pennyroyal is used for flavoring.
P In manufacturing, pennyroyal oil is used as a dog and cat flea repellent; and as a fragrance for detergents, perfumes, and soaps.

T How effective is it?
P 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.
P The effectiveness ratings for PENNYROYAL are as follows:
t 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.
- Pneumonia.
- Stomach pains.
- Weakness.
- Fluid retention.
- Killing germs.
- Skin diseases.
- Other conditions.
P More evidence is needed to rate the effectiveness of pennyroyal for these uses.

T How does it work?
P There isn't enough information available to know how pennyroyal might work.

T Are there safety concerns?
P Pennyroyal oil is LIKELY UNSAFE when taken by mouth or applied to the skin. It can cause serious liver and kidney damage, as well as nervous system damage. Other side effects include stomach pain, nausea, vomiting, burning of the throat, fever, confusion, restlessness, seizures, dizziness, vision and hearing problems, high blood pressure, abortion, lung failure, and brain damage.
P Repeated use of an alcoholic pennyroyal leaf extract over a period of 2 weeks has been linked to a death.
P Not enough is known about the safety of using pennyroyal leaf as a tea.
t Special precautions & warnings:
P 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.
P Pennyroyal leaf tea seems to be able to start menstruation, which could also threaten a pregnancy.
P 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.
P Kidney disease: The oil in pennyroyal can irritate the kidney and make existing kidney disease worse.
P Liver disease: The oil in pennyroyal can cause liver damage and might make existing liver disease worse.

T Are there interactions with medications?
P It is not known if this product interacts with any medicines.
P Before taking this product, talk with your health professional if you take any medications.

T Are there interactions with herbs and supplements?
P Iron
P Pennyroyal might reduce the absorption of iron supplements.

T Are there interactions with foods?
P Iron
P Pennyroyal appears to reduce the absorption of iron from foods.

T What dose is used?
P The appropriate dose of pennyroyal depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for pennyroyal. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

T Other names
P American Pennyroyal, Dictame de Virginie, European Pennyroyal, Feuille de Menthe Pouliot, Frétillet, Hedeoma pulegioides, Herbe aux Puces, Herbe de Saint-Laurent, Huile de Menthe Pouliot, Lurk-In-The-Ditch, Melissa pulegioides, Mentha pulegium, Menthe Pouliot, Menthe Pouliote, Mosquito Plant, Penny Royal, Pennyroyal Leaf, Pennyroyal Oil, Piliolerial, Poleo, Pouliot, Pouliot Royal, Pudding Grass, Pulegium, Pulegium vulgare, Run-By-The-Ground, Squaw Balm, Squawmint, Stinking Balm, Tickweed.

T Methodology
P To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.

T References
- 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.

