A composition comprising from about 1 weight part to about 10 weight parts a saturated carboxylic acid having from 2 to about 20 carbon atoms from about 0.1 weight parts to about 10 weight parts an antifungal compound and from about 80 weight parts to about 99 weight parts skin-penetrating gel wherein the saturated carboxylic acid, the antifungal compound, and the skin-penetrating gel together comprise 100 weight parts. In a particular example of the composition, the saturated carboxylic acid having from 2 to about 20 carbon atoms is acetic acid and the antifungal compound is thymol. A method of treating onychomycosis in a patient, comprising applying the composition. The method provides a safe, effective treatment of onychomycosis.
