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Generic name: pennyroyal [ PEH-nee-roy-al ]
Drug class: Herbal products

Medically reviewed by on Jul 25, 2022. Written by Cerner Multum.

What is pennyroyal?

Pennyroyal is a plant also known as Dictame de Virginie, European Pennyroyal, Feuille de Menthe Pouliot, Frétillet, Hedeoma pulegioides, Herbe aux Puces, Herbe de Saint-Laurent, Lurk-In-The-Ditch, Melissa pulegioides, Mentha pulegium, Menthe Pouliot, Mosquito Plant, Piliolerial, Poleo, Pouliot Royal, Pudding Grass, Pulegium, Run-By-The-Ground, Squaw Balm, Squawmint, Stinking Balm, Tickweed, and other names.

Some uses not proven with research have included treatment of muscular spasms, intestinal gas, pneumonia, weakness, stomach pain, fluid retention, skin conditions, and others.

It is not certain whether pennyroyal is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Pennyroyal should not be used in place of medication prescribed for you by your doctor.

Pennyroyal is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Pennyroyal may also be used for purposes not listed in this product guide.


Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

Before using pennyroyal, talk to your healthcare provider. You may not be able to use pennyroyal if you have certain medical conditions.

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

Pennyroyal is considered likely unsafe to use during pregnancy. There is some evidence that pennyroyal in high doses can cause abortion. It can also cause kidney and liver damage to the mother and be fatal. Do not use this product without medical advice if you are pregnant.

Pennyroyal is considered likely unsafe to use if you are nursing a baby. Do not use this product without medical advice if you are breast-feeding a baby.

Do not give any herbal/health supplement to a child without medical advice. Pennyroyal is specially unsafe for children and can cause liver or nervous system damage and even death.

How should I take pennyroyal?

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use pennyroyal, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Do not use different formulations of pennyroyal (such as tablets, liquids, and others) at the same time, unless specifically directed to do so by a health care professional. Using different formulations together increases the risk of an overdose.

Call your doctor if the condition you are treating with pennyroyal does not improve, or if it gets worse while using this product.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra pennyroyal to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking pennyroyal?

Follow your healthcare provider's instructions about any restrictions on food, beverages, or activity.

The repeated use of pennyroyal extract over a period of 2 weeks has been linked to death.

Pennyroyal side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using pennyroyal and call your healthcare provider at once if you have:

  • seizures;

  • vision or hearing problems; or

  • breathing difficulty.

Common side effects of pennyroyal may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect pennyroyal?

Other drugs may interact with pennyroyal, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Do not take pennyroyal without medical advice if you are using any of the following medications:

  • medicine for high blood pressure; or

  • iron supplements.

This list is not complete. Other drugs may interact with pennyroyal, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this product guide.

Further information

  • Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.