Within the scope of studies on efficacy of skin disinfection an alcoholic preparation with a cation-active substance (Octeniderm) was tested by way of the quantitative cotton swab method. To study the remanent effectiveness the skin of the upper arm was contaminated with Staph. epidermidis (10(2), 10(3) and 10(6)/cm2 skin) a) 1 minute and b) 2 h after disinfection. Swabs of the contaminated skin areas were taken after 1 min, 10 min and 2 h. It was shown, that Octeniderm compared with 70% Isopropanol and with the preparation without the active substance lead to a significant higher reduction of the contamination flora. Recent studies showed, that alcoholic disinfection of skin areas with many sebaceous glands was as good as inefficacious. A first experiment with Octeniderm on the forehead brought a significant better effect than 70% Isopropanol, but too the mean log reduction factors (RF) amount only to 0.76 for the aerobic and 0.64 for the anaerobic bacteria (exposure time of the disinfectant: 10 min) respectively 0.75 (aerobe) and 0.95 (anaerobe) one hour after disinfection.