Also indexed as:Hedeoma pulegoides, Mentha pulegium
Pennyroyal: Main Image© Martin Wall
Botanical names:
Hedeoma pulegoides, Mentha pulegium

How It Works

Like all mint family plants, pennyroyal owes much of its medicinal activity to the presence of a volatile oil. The primary component of this oil is known as pulegone. Pulegone is converted to menthofuran by the body. If large enough amounts of pulegone are consumed, the amount of menthofuran produced can seriously damage the liver and nervous system.3 Smaller amounts of the volatile oil contained in the whole plant appear to have mild, smooth, muscle-relaxing effects that might help explain the historical use of pennyroyal for indigestion, stomach cramps, and cough.4 No modern clinical trials have been completed to support these indications, and other herbs with soothing effects on the gastrointestinal tract, such as chamomile and peppermint, have a much greater history of safety than pennyroyal.

How to Use It

For adults (excluding pregnant or nursing women, children, and people with liver or kidney disease), a tea of pennyroyal can be prepared by putting 1–2 teaspoons (5–10 grams) of the herb in 1 cup (250 ml) of boiling water and allowing it to steep for 10–15 minutes.5 Up to 2 cups (500 ml) per day can be drunk. Pennyroyal tincture can be mixed with a skin cream and applied topically to repel insects, though it is unknown whether this is effective due to a lack of scientific study. The tincture and volatile oil are not recommended for internal use.

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The information presented by Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2018.