Malignant hyperthermia is a well-recognized syndrome of uncertain etiology. The confusing facts are: the variety and different nature of the triggering agents, the variation in time of onset of rigidity and fever coupled with a variation in response to succinylcholine, the lack of family history in some patients, and its occurence in some who have had previously normal general anesthetics. A case is a 23 year old relatively healthy male patient in whom subtotal gastrectomy was performed under N2O-O2-ether and gallamine anesthesia with induction after pentothal sodium and succinylcholine. This was complicated by an abrupt, high rise in body temperature, muscle rigidity, flushing with peripheral cyanosis, disseminated intravascular coagulation and hyperpnea 40 minutes after induction. He died 3 hours after cessation of anesthesia without effective response to any active antipyretic therapy. The etiologic factors, incidence, clinical feature, prevention, treatment and prognosis of malignant hyperthermia are discussed.