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What is Pennyroyal?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Pennyroyal is the common name for two different plants, the American Hedeoma pulegioides and European Mentha pulegium. Both plants are in the family Lamiaceae, or mint, which includes a wide assortment of plants which are useful medicinally and for cooking. Pennyroyal, however, contains a toxin called pulegone, which is extremely dangerous for the liver and kidneys. Despite folklore surrounding pennyroyal's potential medical applications, it is not safe to ingest, especially in the form of essential oil.

Both pennyroyal plants have small opposite oblate leaves on long stems which are capped with blue to purple flowers. European pennyroyal has a more trailing growth habit, while American pennyroyal tends to grow upright. Both plants have a strong and distinctive oder, and can be used fresh, dried, or pressed for the essential oil, which is potent and very pungent. The plant is often used as an herbaceous border, especially in gardens for the blind, as the strong scent helps them find the borders of flower beds.

Despite popular legend, self-treating with pennyroyal is not wise in the event of an unwanted pregnancy.
Despite popular legend, self-treating with pennyroyal is not wise in the event of an unwanted pregnancy.

Although pennyroyal is not safe to ingest, it does have potentially useful applications. Pennyroyal is a highly effective insect repellent, and is often included in commercial products designed to deter insects. Collars made from dried pennyroyal can be used on pets to naturally reduce fleas, and pennyroyal extract can also be applied to pet collars, bedding, and used generally around the house. The pungent odor of pennyroyal will discourage a number of members of the insect community.

Sage is a folk remedy for painful and irregular menstruation.
Sage is a folk remedy for painful and irregular menstruation.

Pennyroyal leaves can also be used to make a refreshing skin wash, although the essential oil should not be used directly on the skin. People who are pregnant or have liver sensitivities should avoid pennyroyal altogether, as it can be very dangerous for them. Although some herbalists say that pennyroyal is safe to drink for digestive complaints and menstrual issues, other herbs are far safer for this application.

Pennyroyal can be an effective form of insect repellent.
Pennyroyal can be an effective form of insect repellent.

In all cases, a doctor should be consulted before taking herbs. For digestive problems, other members of the mint family are very soothing for the stomach, such as peppermint and spearmint. Black cohosh, yarrow, fennel, ginger, and sage may be taken to make menstrual cycles more regular and less painful. Pregnant women should be especially careful about which herbs they take.

Some believe pennyroyal may regulate a woman's menstrual cycle.
Some believe pennyroyal may regulate a woman's menstrual cycle.

Popular legend also claims that pennyroyal is an effective abortifacient. Unfortunately, women have died from self-administrations of pennyroyal, the essential oil in particular. If you are facing an unwanted pregnancy, please seek professional help and counseling.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon342730

This is very confusing as there is a product called yerba mate tea imported from Argentina that includes the pennyroyal (poleo in spanish) and claims on the bag that it "protects" the liver. These are dangerous claims considering who is right. I will further investigate which one is correct. I trust plants more than I trust made up pharma pills.

anon7546

good morning! i must say i have taken penny royal menstrual problems. i see my period every other month, however i will encounter lots of pain when i'm seeing my period and breasts are tender. since i taken it i haven encountered no pain, but my period is taking longer than the norm. i see it Dec 14-Jan-03, started again the Jan 13 until now. please advise me thank you.

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    • Despite popular legend, self-treating with pennyroyal is not wise in the event of an unwanted pregnancy.
      By: Igor Mojzes
      Despite popular legend, self-treating with pennyroyal is not wise in the event of an unwanted pregnancy.
    • Sage is a folk remedy for painful and irregular menstruation.
      By: Jita
      Sage is a folk remedy for painful and irregular menstruation.
    • Pennyroyal can be an effective form of insect repellent.
      By: Henrik Larsson
      Pennyroyal can be an effective form of insect repellent.
    • Some believe pennyroyal may regulate a woman's menstrual cycle.
      By: blueringmedia
      Some believe pennyroyal may regulate a woman's menstrual cycle.
    • Pennyroyal poses significant danger if consumed by pregnant women.
      By: yarkovoy
      Pennyroyal poses significant danger if consumed by pregnant women.
    • Pennyroyal essential oil should not be ingested or applied directly to the skin.
      By: Lucie Říhová
      Pennyroyal essential oil should not be ingested or applied directly to the skin.
    • Some herbalists believe that pennyroyal is safe to drink for menstrual issues.
      By: fmarsicano
      Some herbalists believe that pennyroyal is safe to drink for menstrual issues.