A series of experiments comparing the taste reactions of human and rats to sodium sucaryl and saccharin are reported. Human subjects liked moderate concentrations of sucaryl about as well as a standard saccharin solution, but preferred saccharin to higher concentrations of sucaryl; rats preferred water to the 3 human-preferred sucaryl solutions, although saccharin preferences were little different from those of humans. It is concluded that the taste mechanisms of rat and human differ, probably in terms of differential thresholds for sweet and bitter. (PsycINFO Database Record (c) 2006 APA, all rights reserved)