noun. erect hairy branching American herb having purple-blue flowers; yields an essential oil used as an insect repellent and sometimes in folk medicine.
noun. Eurasian perennial mint have small lilac-blue flowers and ovate leaves; yields an aromatic oil.
1. Adjective You can use extracted menthol or take it in the form of peppermint, eucalyptus or pennyroyal concoctions. 2. Noun, singular or mass Always be sure to dilute pennyroyal, as it can be toxic when used at full strength.
