Menthol is an organic compound with colorless needle-like crystals or granules, and is the main component in peppermint and euphorbia essential oils. There are eight isomers of menthol, levomenthol has a minty aroma and a cooling effect. The other isomers have no cooling effect and are used as flavoring agents in toothpaste, perfumes, beverages and candy. In medicine, it is used as a stimulant, acting on the skin and mucous membranes, and has a cooling and anti-itching effect. Internally it is used for headaches, and inflammation of the nose, throat and throat. Menthol can be purified from natural peppermint crude oil, or can be made synthetically.