Children otherwise suitable for same-day discharge may be admitted to the hospital solely because they are known or suspected to be malignant hyperthermia-susceptible (MHS). To determine whether their hospitalization is necessary, the medical charts of 303 children labeled MHS who had undergone surgery with anesthesia free of malignant hyperthermia-triggering agents on 431 occasions between 1981 and 1990 were reviewed. Eighteen of these patients (25 cases) who were subsequently identified as biopsy-negative were excluded from the study. We recorded the reason for the MHS label and the perioperative management and outcome of the cases. Fifty-eight percent of procedures were followed by hospital admission solely because of the patient's MHS label. None of the 25 children (33 cases) with biopsy-proven malignant hyperthermia developed intraoperative or postoperative pyrexia. Ten children suspected to be MHS developed pyrexia greater than 38.5 degrees C. These episodes were not considered to be malignant hyperthermia and were not treated with dantrolene. None of the remaining 275 patients exhibited any features of malignant hyperthermia, although one had an adverse reaction to radiologic contrast medium. On the basis of our retrospective analysis, postoperative admission to the hospital solely on the basis of the MHS label is not warranted.