Thirty-two patients who complained of episodes of ravenous overeating which they felt unable to control (bulimia) were asked to describe their behaviour and symptoms. There was considerable variation both between and within individuals, but a number of factors were defined which appeared to be common to all with the complaint. It is difficult to set up strict criteria for the recognition of bulimia, and those that have recently been proposed are criticized in the light of our present findings. Bulimia is usually associated with an excessive concern about body weight. It occurs in patients with anorexia nervosa, in whom it is often a relatively early feature of the illness, but it is also found in subjects of normal weight or obese subjects who have never been emaciated. Episodes of bulimia are usually preceded by dysphoric mood states. The gorging may alleviate the dysphoria temporarily, but many patients later experience negative feelings such as depression and self-depreciation. The ability to induce vomiting after a bulimic episode is a major influence determining the clinical presentation.