The authors report a retrospective study of 11 cases of malignant hyperthermia. The mean age of the patients was 5 months and 3 weeks. Clinical features included severe hyperthermia (greater than 41 degrees C), seizures, coma, collapse, rhabdomyolysis, acute renal failure and functional renal failure. Three infants died. Four patients presented neurological damages. Four recovered fully. The authors discuss the difficulties of diagnosis, the nosological position and the pathophysiology of this syndrome.