Cats reject saccharin and cyclamate and are indifferent to dulcin, although they, like other mammals, prefer sucrose. The rejection threshold for saccharin found for 10 cats in the present 2 experiments, 0.0001 M, was about 2 log steps lower than a previously reported rejection threshold for sodium saccharin. Water produced a taste in Ss adapted to their own saliva. The high sodium saccharin was masked by the taste of the water solvent; however, saccharin may also be somewhat more aversive to the cat than sodium saccharin. Saccharin may produce an aversive taste because it stimulates receptor sites sensitive to substances bitter to man as well as those sensitive to sugars. In addition, saccharin may not be an effective stimulus for all sugar-sensitive sites. (17 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)