Such eating disorders as anorexia nervosa, bulimia nervosa, and binge eating disorder are associated with significant morbidity and mortality in women. The etiology of these disorders and the causes of women's increased vulnerability to them remain obscure. The lack of understanding of the biological bases of normal and abnormal human eating behavior impedes development of effective pharmacologic treatment for eating disorders. A review of basic research, implicating estradiol in the physiologic control of eating in laboratory animals, shows potential heuristic and mechanistic significance for normal and disordered eating in women. Furthermore, accumulating evidence indicates that estradiol may decrease meal size by increasing the potency of the satiating actions of some gut peptides, especially cholecystokinin. These findings suggest there may be hope for treatment through manipulation of estradiol's interactions with both peripheral psychological and central neural controls of eating.