Opportunities of spontaneous wheel running induced aversion in rats to the taste consumed before the running. Eight thirsty rats of Wistar strain were daily allowed to drink one of two taste solutions (sucrose or sodium chloride, say A) followed by confinement in a wheel or another taste solution (say B) followed by confinement in a Skinner box. Repeated training with Tastes A and B made the rats drink Taste A less than Taste B. Post-training two-bottle choice tests also showed clear demonstration of wheel-running-induced aversion to Taste A. These results confirmed those from Lett's laboratory and expanded the generality of the phenomenon in respect to strain of rats, deprivation conditions of the subjects, tastes, and other details. Furthermore, our procedure rejected three accounts alternative to wheel-induced aversion to Taste A.