Onychomycosis are the more prevalent nail infections. They may be caused by dermatophytes (Tricophyton rubrum and T. mentagrophytes) as well as by Candida species and a number of other moulds. Laboratory confirmation of a clinical diagnosis of onychomycosis should be obtained before the beginning of oral treatment, because of the long periods of treatment that are usually required, the high costs of such treatments, and the potential side effects of the drugs. However, terbinafine, itraconazole and fluconazole are effective against the dermatophytes in nail. Moulds infections of nails more seldom respond to antifungal therapy.