Ten patients with pyoderma gangrenosum, seven female and three male, 25 to 94 years old, mainly with multiple lesions, have been treated with clofazimine, 100 mg three times daily. Associated disease was registered in three patients: diabetes mellitus, a previous adenocarcinoma of the colon treated by hemicolectomy, and pustulosis palmoplantaris. In a further patient, M-component was found in the serum. In seven cases the lesions were completely healed by two to five months of therapy, and in three cases the ulcers healed partially. Side effects were redness of the skin in seven cases and dryness of the skin in two patients. No hematological side effects occurred. The working mechanism is still obscure. (Arch Dermatol115:851-852, 1979)