Pennyroyal (Mentha pulegium)

It is an aromatic herb. Its strong flavor adds flavor to soups and stews. The infusion (15-20gr/l) of fresh plant stimulates bile secretion, fights stomach pain and facilitates sleep. In external use, the fresh plant poultice is useful for wounds, insect bites and, placed on the forehead, for headache. Another use, less known but which gives it its name, is to repel fleas. It is another of our aquatic plants, although it needs less water than the previous ones. It breeds in streams and well springs.


Pennyroyal (
Mentha pulegium
) is one of the best known species of the Mentha genus. From the labiatae family, it is a cespitose perennial with rhizomatous roots that grows well in humid places.

Its erect quadrangular, highly branched stems can reach 30 to 40 cm in length. The leaves are lanceolate and slightly toothed, medium to dark green in color and are arranged opposite each other along the stems. The tiny pink flowers are borne clustered in tight globose inflorescences.

This aromatic plant has been known for centuries throughout the Mediterranean basin and Western Asia, where it grows spontaneously, for its carminative and relaxing properties and even as an emmenagogue (which favors the onset of menstruation), taken as an infusion.

The medicinal use of pennyroyal is old, as evidenced by its presence in the Capitulare de villis vel curtis imperii, an order issued by Charlemagne calling on his countryside to cultivate a number of herbs and condiments including “puledium” now identified as Mentha pulegium. It was attributed with principles that help erection.

The leaf is usually used (although the whole plant can be used) which mostly contains pulegone, menthol and other terpene substances such as menthone, isomenthone … (in smaller proportion). The whole gives a carminative effect (facilitates the expulsion of intestinal gas) and digestive as well as emmenagogue (regulates menstruation). In mild bronchial affections it also has some action as an expectorant and antitussive (topically). It is used in infusions as a relaxant and is said to favor the expulsion of the placenta after childbirth.


It is not advisable for people suffering from liver diseases since pulegone, which is the active ingredient in the highest concentration, has a highly hepatotoxic effect. The essential oil is also extracted, which is the one that presents this toxicity in the liver and lungs, besides being abortive in animals.

The whole plant contains essential oil (0.5 to 1 %) based on pulegone, an unsaturated ketone. It also contains menthone, limonene and other ketones. Digestive and stomach tonic. Expectorant and antitussive. Emmenagogue and antispasmodic. Vermifuge. Antiseptic.