Pennyroyal (Mentha pulegium)
Overview
Pennyroyal (Mentha pulegium) is a strongly aromatic perennial mint growing up to about 16 in (40 cm), with oval, serrated leaves and whorls of small, lilac flowers. Often used as an herbal tea to encourage sweating, pennyroyal helps break fevers, soothe colds, and promote digestion. Historically prized for menstrual regulation and as a flea repellent.
Traditional uses & properties
Antispasmodic & Carminative: Helps relieve colic, gas, flatulence, and mild digestive cramps. Diaphoretic: Encourages sweating, aiding in fever management and symptom relief for colds. Emmenagogue: Can help stimulate or regulate menstruation (avoid if pregnant or if bleeding is heavy). Insect Repellent: Known to repel fleas and mosquitoes; used in sachets or as a dilute external spray.
Preparations & dosage
4–8 ounces up to 4 times daily
Fresh leaf (1:2, 95% alcohol); recently dried leaf (1:5, 50% alcohol); 1–2 ml (0.2–0.4 tsp.) in hot water
Safety & precautions
Pregnancy: Stimulates uterine contractions; avoid during pregnancy. Essential Oil: Highly toxic if ingested (reports of fatalities); do not take internally. Menstrual Flow: Avoid if you already have heavy bleeding.
Drug & food interactions
Pennyroyal may reduce the absorption of iron compounds.
No interactions found.
No interactions found.
Pennyroyal tea reduces iron absorption similarly to conventional tea. In a study in 9 healthy subjects, a 275mL serving of pennyroyal tea reduced the absorption of iron in a 50 g bread roll by about 70%. The tea was prepared by adding 300mL of boiling water to 3 g of the herbal tea, then infusing for 10 minutes before straining and serving. In this study, the inhibitory effect of pennyroyal tea on iron absorption was modestly less than that of black tea (Assam tea, Camellia sinensis L.), which is known to inhibit iron absorption.
Habitat
Native to Europe and western Asia, and now naturalized in the Americas, pennyroyal grows in damp places and is gathered when flowering in summer. The aerial parts (leaves and flowers) are dried or used fresh.