menthol, white crystalline substance with a characteristic pungent odor. It is derived from the oil of the peppermint plant, Mentha piperita (see mint), or prepared synthetically from coal tar. An alcohol, menthol is freely soluble in ethyl alcohol, ether, and chloroform. It is a local anesthetic and helps relieve itching, and because it imparts a tingling sensation to the skin, it is used in after shave lotions and skin fresheners. It is also used in throat lozenges, inhalers, and as a flavoring.