Pennyroyal is perhaps the shortest member of the mint family and is valuable in aromatherapy and herbal medicine. It is also an insecticide against moths, fleas and other pests, making it beneficial to have in a garden full of vulnerable plants. Frequently grown as a groundcover, this perennial herb typically measures about six to twelve inches and has small blue to lilac flowers. Fresh herb should be harvested when the plant is about to flower. As indicated in the popular Nirvana song, “Pennyroyal Tea,” the dried herb can be used for creating a tea that settles the stomach. Pennyroyal is also regarded as a menstrual stimulant because it increases blood flow to the pelvic region. Although the tea is regarded as acceptable to drink in moderation, it should always be avoided by pregnant women because pennyroyal was once used to induce abortion in the early stages of pregnancy. The essential oil is extremely concentrated and should never be taken internally because it can have negative or even deadly effects. Use of the essential oil is strictly limited to aromatic applications, being added to perfumes and bath water. Pennyroyal is also an important herb in wiccan philosophy with a connection to luck in business and finance.