Malignant hyperthermia (MH) is a potentially fatal complication of general anesthesia following exposure to a depolarizing muscle relaxant and/or volatile anesthetics. MH is inherited as autosomal dominant and is thought to result from disordered Ca2+ regulation by the sarcoplasmic reticulum of the skeletal muscle. The mortality is still approximately 15% in Japan. It is difficult to diagnose by usual examinations preoperatively. Therefore, early detection, prompt treatment, discontinuation of triggering agents, and sufficient administration of dantrolene are needed.