May 25, 1979

Plant known for centuries still causes problems today

JAMA. 1979;241(21):2246-2247. doi:10.1001/jama.1979.03290470006003

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An abortifacient used in ancient Rome is causing present-day problems.

It is the oil of a plant known as the pennyroyal, mosquito, or squawmint (Mentha pulegium). Public health officials say pennyroyal oil has been involved in three recent poisonings in Colorado, one of which was fatal.

The plant is found from Canada to Florida and at least as far west as Nebraska. Pennyroyal oil is related to turpentine and is sometimes marketed as an insect repellent or herbal fragrance. It has been used for at least 2,000 years. While its action is believed to involve irritation of the uterus and bladder, triggering reflex contractions, some users contend that, taken as an herbal tea, pennyroyal is calming and diaphoretic and induces menses. There is, however, no documentation that it can induce abortion at other than near-lethal dosage.

Julian Gold, MD, told Epidemic Intelligence Service colleagues at a recent Atlanta conference that