This project is based on the hypothesis that induced hyperthermia may prevent or treat the prolonged muscular relaxation caused by intraoperative hypothermia or by unknown origin. In some researches, one of the causes of postoperative respiratory depression is residual curarization which is usually resulted from hypothermia. But, there is no articles about the twiteh response in hyperthermia. The 10 mongrel dog with no muscular, renal or hepatic disease were classfied into 3 groups according to the type of muscle relaxants, atracurium group, pancuronium group and norcuron group. In each case, induced hyperthermia was applied on one side and normothermia was maintained on the other side. Muscular twitch response from the TOF stimulation was recorded. This experiment was repeated with tourniquet application in order to avoid the effect of systemic circulation. The muscular twitch response appeared faster in hyperthermia group than in normothermia group regardless of the type of muscle ralaxants. Now, therefore, we can utilize the results by inducing hyperthermia to treat and prevent the postoperative hypoxia caused by intraoperative hypothermia as well as excessive use or inade- quate reverse of muscle relaxants.