Pennyroyal (Mentha pulegium) is a perennial plant, erect or lying, up to 50 cm high, very aromatic. Its leaves are opposite, elliptical, covered with fine hairs, and emit an intense minty fragrance when crushed. The flowers are pale pink in color and are grouped in globose and compact whorls in the axils of the leaves.
For medicinal uses the whole plant is collected, which we can find dry for infusion. It contains an essential oil with menthol, pulegone, isopulegone, piperitenone and limonene, as well as bitter principles and tannins.
Formerly it had been used as a slimming; taken with wine it was said to act as an antidote to snake bites, and mixed with vinegar, it served to revive after fainting.