Social animals both increase and decrease their stress levels by interacting with conspecifics. The present study examines the effect of interaction with a conspecific on conditioned taste aversion in 32 male mice. Subjects were injected with lithium chloride immediately after drinking saccharin solution for 30min. They were then exposed to a male conspecific for 3h following the poisoning. In the subsequent three consecutive days of two-bottle tests involving a choice between saccharin solution and water, they showed attenuated conditioned taste aversion compared with controls exposed to no conspecific after poisoning. These results confirm social interaction with a conspecific reduces conditioned taste aversion in mice. The implications of these findings are discussed with regard to social buffering effect and stress-induced analgesia.