Pennyroyal, with the scientific name of Menthe Pulegium, is from the mint family and its main ingredient is a fragrant volatile oil or menthol oil, some tannins, resins and lots of A, B, and C vitamins and calcium. Pennyroyal is a good alternative to many antibiotics, so it can be used to treat cold, digestive problems, and relieving sore throats and nausea.