Parts used: Entire plant Properties Alterative, antispasmodic, antivenomous, aromatic, carminative, decongestant, diaphoretic, diuretic, emmenagogue, nervine, oxytocic, parasiticide, sedative, stimulant, stomachic Pennyroyal contains a volatile oil that works to remove gas from the stomach. It can be consumed as a tea or used as a footbath. If taken a few days before menstruation is due, it can help increase a suppressed flow. A tea is also beneficial in relieving cold symptoms and promoting perspiration. The herb has a strong minty odor and is used externally to repel insects such as fleas, flies and mosquitoes. Pennyroyal tea is suggested for use as a decongestant for coughs and colds. It is a member of the mint family and helps relax the digestive tract and soothe the stomach.