Among eating disorders, the incidence and prevalence of anorexia nervosa and bulimia nervosa are reported to be on the increase. The diverse--and possibly fatal--consequences of these disorders are reviewed by the authors. The process of fasting-dieting, the bingeing episode or the methods applied for weight reduction (self-vomiting, use of laxatives, diuretics, diet pills, extreme exercise) can be harmful to the organism, either alone, or in combination. After reviewing the gastrointestinal, cardiovascular, pulmonary, renal, hematological, gynecological, endocrine, neurological, orthopedic, dermatologic, laryngologic and dental complications, the authors high-light anamnestic data and clinical signs on the basis of which eating disorders can be diagnosed.