Groups of 50 NMRI-mice of each sex were treated twice weekly with 0.2 mlof 0, 0.018, and 0.18 ml of 3-Chloro-2-hydroxypropyl- trimethylammonium chloride dissolved in a 10% aqueous ethanol solution. This corresponds to doses of 0, 13.8, and 138 mglanimal applied to the clipped dorsal skin (2 cm2) of the animals. The study was terminated after 89 weeks forfemale animals and 105 weeks for male animals when the 25% survival limit was reached.