Bulimia nervosa is an eating disorder that is characterized by chronic binge eating followed by harmful dietary habits (e.g., purging, fasting) to prevent any subsequent weight gain. However, bulimia should not to be confused with anorexia nervosa, another eating disorder characterized by chronic, strict calorie restriction and/or purging behaviors. Unlike anorexia nervosa patients, who must weigh more than 15 percent below the expected range for their age and body size, patients with bulimia are almost never underweight. 

There are two types of bulimia nervosa:

• Purging bulimia. The most common type of bulimia in which patients regularly engage in purging behaviors to control their weight. The most widely used method is self-induced vomiting. Other purging methods include the misuse of laxatives (usually mild agents that induce bowel movements), diuretics, enemas (injecting liquid into the intestines through the anus to empty the bowels) or emetics (e.g., syrup of ipecac) to induce vomiting.
  
  
• Nonpurging bulimia. In this type of bulimia, patients do not engage in purging methods to avoid weight gain. Rather, individuals with nonpurging bulimia follow episodes of binge eating by strict dieting, fasting and/or excessive exercise.