The authors investigated whether conditioned taste aversion and immunosuppression took place when water was available during conditioning and test protocols. The authors elicited taste-aversion conditioning and immunosuppression in outbred CD1-strain mice by pairing a conditioned stimulus (sucrose or saccharin solution) with an unconditioned stimulus (cyclophosphamide) that causes gastrointestinal upset and is immunosuppressive. The authors introduced a new conditioning protocol: 5 pairings of a saccharin solution with a low-dose injection of cyclophosphamide. Under these conditions, the authors generated conditioned aversion to saccharin but did not generate conditioned decrease of the antibody response. The authors conclude that taste-aversion conditioning, but not immunosuppression conditioning, occurred under partial water deprivation.