The skin thinning effect of discontinuous topical clobetasol-17-propionate applications was tested in human volunteers. Application frequencies were daily (1/0), every third day (1/2), every fifth day (1/4), every seventh day (1/6) and every ninth day (1/8). Clobetasol-17-propionate was administered topically under occlusion for 1 h. The treatment period was 41 days. There were no differences of the skin thinning effect of daily and 1/2 administration. The skin thinning effect of 1/4, 1/6 and 1/8 was smaller but also significant compared to controls. The curves demonstrating skin thinning effects initially were dropping off and reached a plateau within about 2 weeks. After finishing application, skin thickness normalized within 2 weeks. Because of these findings, a treatment intervall of 3 days is discussed as therapeutically efficient.