Pennyroyal

Pennyroyal (Mentha pulegium) is a flowering perennial herb in the mint family, Lamiaceae. It forms low, creeping mats with small oval leaves and clusters of purple to mauve flowers in summer. Native to Europe, North Africa, and parts of Asia, pennyroyal has been introduced elsewhere as an ornamental and herbal plant. It prefers moist, well-drained soils and can tolerate partial shade; it often spreads by runners and can become invasive in suitable climates.

Culinary and traditional uses are limited today due to safety concerns. The leaves have a minty aroma and have been used sparingly as a flavoring in some regional cuisines. Pennyroyal has also been used in traditional medicine and as an insect repellent, but these uses are limited by toxicity and safety warnings. The essential oil, richly concentrated in pulegone, has been employed in perfumery and, historically, as an herbal remedy; however, it is highly toxic.

Safety and toxicity: Pulegone is a hepatotoxic compound. Ingesting pennyroyal oil or large amounts of the plant can cause severe liver and kidney damage, seizures, coma, and death. Because of these risks, authorities advise against internal use of pennyroyal oil or preparations containing high pulegone concentrations. Pets and children should be protected from exposure, and ornamental growth should be managed to prevent accidental ingestion.

See also: Mentha, essential oil toxicity.