The clinical and physiologic features of anorexia nervosa seem to be consequences of a complex interaction among psychologic abnormalities, endocrine disturbances, and malnutrition. Although a spectrum of psychologic disorders has been observed, distortion of body image, weight phobia, disordered perception of hunger and satiety, and a sense of ineffectiveness are encountered most frequently. The impaired secretion of luteinizing hormone-releasing factor, release of gonadotropins, and production of estrogens reflect a defect in the hypothalamic-anterior pituitary-gonadal axis. Because most of the endocrine abnormalities are reversible with improved nutrition, they are probably secondary to malnutrition rather than to hypothalamic dysfunction. Hypercarotenemia observed in 16 of 21 patients studied recently seems useful in differentiating anorexia nervosa from other forms of malnutrition and weight loss. A combined medical and psychiatric approach has been successful in drastically reducing the mortality of this disorder.