Malignant hyperthermia, a rapidly progressive, frequently lethal syndrome was not described until quite recently. Although treatment with the drug dantrolene has changed its face, a clear understanding and deep respect for the syndrome are necessary to keep fatalities and tragic sequelae to a minimum. The etiology and pathophysiology, preanesthetic diagnosis, incidence, management of the acute crisis, and anesthesia for susceptible patients are discussed, and a successfully treated fulminant case is analyzed.