Fifty-five patients with griseofulvin-unresponsive dermatophytosis caused by Trichophyton rubrum were treated with itraconazole. They had either tinea corporis or "dry type" infections of the palms, soles, or nails. The following sites were affected: trunk (12 infections), soles (47), toe webs (52), palms (26), fingernails (29), and toenails (42). Patients were treated with oral itraconazole until clinical and mycologic remission were achieved. Response rates and mean times to recovery were as follows: trunk, 100%, 1.5 months; soles, 83%, 6.7 months; toe webs, 90%, 7.2 months; palms, 96%, 4.6 months; fingernails, 90%, 5.4 months; and toenails, 76%, 10.3 months). In a 6-month follow-up period 7 of 30 patients with toenail infections who had responded to treatment had a clinical and mycologic relapse, usually of one nail. Side effects were minimal but included abdominal discomfort (three patients), headache (one), and weight gain (two). No persistent abnormalities in blood biochemistry were seen, even in patients who received itraconazole for more than 9 months.