Pennyroyal, the name of two aromatic herbs. The European, or garden, pennyroyal, native to Europe, and sometimes cultivated in the United States, is a low-growing perennial plant with small bluish flowers. The downy, oval leaves are used as a sweet seasoning. The similar-looking American, or false, pennyroyal of eastern North America is a common annual plant of woods and roadsides. Oil from its leaves is used in mosquito repellants.
The European pennyroyal is Mentha pulegium; American, Hedeoma pulegioides. Both belong to the mint family, Labiatae.