In a double-blind trial over a 2-week period in 34 patients with psoriases vulgaris, clobetasol propionate cream was shown to be more effective than betamethasone valerate cream. In a further 16 patients whose psoriasis had not responded to betamethasone valerate ointment, treatment with clobetasol propionate ointment was substituted. Fourteen of the 16 patients experienced a rapid improvement of their lesions.