Bulimia nervosa is an eating disorder marked by recurrent episodes of binge eating followed by compensatory behaviors intended to prevent weight gain. The binges involve eating large amounts of food in a short time with a sense of loss of control; the compensatory acts commonly include self-induced vomiting, misuse of laxatives or diuretics, fasting, or excessive exercise.

Unlike anorexia, people with bulimia are often of normal weight or overweight, so the disorder may remain hidden longer. Medical risks include electrolyte imbalances that can affect the heart, dental erosion from repeated vomiting, and gastrointestinal damage. Psychological features frequently include body dissatisfaction, mood instability, and a harsh self-evaluation that is overly dependent on shape and weight.

The disorder typically begins in late adolescence or early adulthood. Treatment with the strongest evidence is cognitive-behavioral therapy specifically adapted for bulimia; certain antidepressant medications can also reduce binge-purge frequency. Recovery is possible, yet the course can be chronic without intervention.

Bulimia is driven by a cycle of restriction, bingeing, and compensation that becomes self-perpetuating. Interrupting that cycle is the central task of treatment.