Toxicity
Pennyroyal essential oil should never be taken internally because it is highly toxic; even in small doses, consumption of the oil can result in death. The metabolite menthofuran is thought to be the major toxic agent. Complications have been reported from attempts to use the oil for self-induced abortion. For example, in 1978, an eighteen-year-old pregnant woman from Denver, Colorado, died within one week after consuming one ounce of concentrated Pennyroyal oil in an attempt to self-induce abortion. There are numerous studies that show the toxicity of pennyroyal oil to both humans and animals.
Since the U.S. Congress passed the Dietary Supplement Health and Education Act in October 1994 all manufactured forms of pennyroyal in the United States have carried a warning label against its use by pregnant women, but pennyroyal is not regulated by the U.S. Food and Drug Administration.
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