Mentha pulegium, commonly pennyroyal, or pennyrile, also called mosquito plant and pudding grass, is a toxic species of flowering plant in the mint family, Lamiaceae, native to Europe, North Africa, and the Middle East. Crushed pennyroyal leaves emit a very strong fragrance similar to spearmint.
Pennyroyal is a traditional folk remedy, emmenagogue, abortifacient, and culinary herb, but is toxic to the liver and has caused some deaths. One tablespoon (15 mL) is sufficient to cause seizures, coma, acute liver injury, and multi-organ failure.
European pennyroyal is related to an American species, Hedeoma pulegioides. Though they differ in genera, they share similar chemical properties.