Herb: Pennyroyal

Latin name: Mentha pulegium

Family: Labiatae

Medicinal use of Pennyroyal:

Pennyroyal has been used for centuries in herbal medicine. Its main value is as a digestive tonic where it increases the secretion of digestive juices and relieves flatulence and colic. Pennyroyal also powerfully stimulates the uterine muscles and encourages menstruation, thus it should not be prescribed for pregnant women since it can procure abortions, this is especially the case if the essential oil is used. The herb is antiseptic, antispasmodic, carminative, diaphoretic, emmenagogue, sedative and stimulant. A tea made from the leaves has traditionally been used in the treatment of fevers, headaches, minor respiratory infections, digestive disorders, menstrual complaints and various minor ailments. It is occasionally used as a treatment for intestinal worms. Externally, an infusion is used to treat itchiness and formication, inflamed skin disorders such as eczema and rheumatic conditions such as gout. The leaves are harvested in the summer as the plant comes into flower and are dried for later use. The essential oil in the leaves is antiseptic, though it is toxic in large doses.

Description of the plant:


40 cm
(1 foot)

August to


Habitat of the herb:

Moist meadows and sandy soils by streams etc.

Edible parts of Pennyroyal:

Leaves - raw or cooked. Used as a flavouring in salads or cooked foods. A spearmint-like flavour, though rather coarser, it is not used very often in Britain. A herb tea is made from the fresh or dried leaves. For drying, it should be harvested as the plant comes into flower.

Other uses of the herb:

An essential oil is obtained from the whole plant, used in soap making and as a cleanser for fabrics. A yield of 14kg of oil per hectare is considered good. The plant has a low spreading habit and can be used as a ground cover, though it is somewhat sparse in the winter and can be invaded by the more aggressive weeds. The growing or dried plant repels fleas, ants, moths, mice etc. Rats and mice intensely dislike the smell of mint. The plant was therefore used in homes as a strewing herb and has also been spread in granaries to keep the rodents off the grain. A strong infusion applied to the face will keep gnats away in the summer. The aromatic leaves are used as an ingredient of pot-pourri.

Propagation of Pennyroyal:

Seed - sow spring in a cold frame. Germination is usually fairly quick. Prick out the seedlings into individual pots when they are large enough to handle and plant them out in the summer. Mentha species are very prone to hybridisation and so the seed cannot be relied on to breed true. Even without hybridisation, seedlings will not be uniform and so the content of medicinal oils etc will vary. When growing plants with a particular aroma it is best to propagate them by division. Division can be easily carried out at almost any time of the year, though it is probably best done in the spring or autumn to allow the plant to establish more quickly. Virtually any part of the root is capable of growing into a new plant. Larger divisions can be planted out direct into their permanent positions. However, for maximum increase it is possible to divide the roots up into sections no more than 3cm long and pot these up in light shade in a cold frame. They will quickly become established and can be planted out in the summer.

Cultivation of the herb:

Moist meadows and sandy soils by streams etc.

Known hazards of Mentha pulegium:

In large quantities this plant, especially in the form of the extracted essential oil, can cause abortions so it should not be used by pregnant women.

Plant information taken from the Plants For A Future.