Groups (9) of rats and 27 groups of hamsters (12/group) each tasted 1 from among 27 different solutions before receiving an i.p. injection of apomorphine, then were tested for aversions to 4 solutions prototypic of human beings'' 4 taste qualities (S, sucrose; N, NaCl; H, HCl; Q, quinine hydrochloride). With most of the solutions that are described as sweet by humans employed as a conditioned stimulus (CS), the rodents acquired an S aversion (exceptions occurring for some artificial sweeteners). With CS described as either predominantly salty or sour by humans, the rodents acquired an N aversion in the former case or an H aversion in the latter case; a Q aversion was also acquired with 2 (including H) of the 3 CS describing as sour. With most of the CS described as predominantly bitter or as having a considerable bitter component by humans, the rodents acquired a Q aversion (and a weaker H aversion). Considerable parallels among the taste sensations of humans, rats and hamsters are indicated. Patterns of activity evoked across 4 classes of peripheral gustatory neurons (those responding best to lingual stimulation with S, N, H, or Q) in rodents when the CS were applied to the tongue were similar to the patterns of aversions across the 4 test stimuli for the CS. Apparently these 4 neural channels mediate the sensations evoked by S, N, H and Q in rats and hamsters, perhaps even in human beings.