Anorexia nervosa and bulimia are appearing with increasing frequency in preadolescents and adolescents. Eating disorders lead to significant physical changes related to starvation and/or purging. These patients should be specifically questioned about taking laxatives, diuretics, or amphetamines to lose weight. Subclinical abnormalities, coupled with the patient's denial, emphasize the need for careful physical examination and laboratory assessment. Preexisting electrolyte, cardiovascular, and thermoregulatory alterations must be recognized so that an appropriate anesthesia plan can follow.