Anorexic and bulimic eating disorders today are rather frequent in adolescent girls and young women of developed industrial countries. News media frequently report such patients, and lay people are interested. For scientists, it is not easy to explain the etiology and pathophysiology of these eating disorders. Clinically, treatment is a challenge. General risk factors for the development of anorexic and bulimic eating disorders are (1) female gender, (2) adolescence, and (3) living in an industrial country. Special risk factors are (1) obesity or mental disorders (eating, depression, substance use), (2) premorbid characteristics (early menarche, childhood obesity, anxiety disorder, low self-esteem, and perfectionism), and (3) premorbid stresses. Biological and sociocultural factors and personally threatening experiences all play a role in the etiology. Especially in early phases of the illness, affected patients do not appear to suffer, are reluctant to admit symptoms, and may avoid necessary treatment. Progress has recently been made in the understanding and treatment of anorexic and bulimic eating disorders.