Most lower gastrointestinal complications among bulimia nervosa patients are associated with the use of stimulant laxatives. Cathartic colon, colonic inertia, or rectal prolapse may arise, but symptoms should subside with cessation of laxative use, or replacement with osmotic laxatives. However, it is important to note that rectal prolapse may also result in anorexia nervosa patients due to malnutrition and the resultant weakening of the pelvic floor muscles. For unclear reasons, laxative use may also cause melanosis coli or blackening of the colon.