Prolapse is a common disease, prolapse refers to the anal part of the swelling out of the anus refers to the anal margin of the swelling bulge or anal canal rectum in the swelling out of the anus. Prolapse is a kind of anal and intestinal diseases, caused by prolapse of anus has many reasons, rectal polyps, anal papilla hypertrophy, hemorrhoids, tumors, etc. will cause prolapse of anus. 1, rectal polyps: lower rectal polyps can be detached from the anus with defecation, can be self-returned, polyp surface for the mucosa, mucosa inflammation was strawberry, detached polyp has a tip, often easy to bleed. 2, anal papilla hypertrophy: in addition to the small triangular, rice-like hypertrophy of the anal papilla, the larger anal papilla can be out of the anus with defecation, part of the self-recovery, and some need to use the hand to return to the position, the clinical only anal discomfort, no pressure and pain, and seldom bleed, it can be a, or a number of. 3, internal hemorrhoids: when the internal hemorrhoids out of the anus, after the hemorrhoid mass of self-recovery for the II stage of internal hemorrhoids; after the hemorrhoid mass can not be reincorporated, need to be reset with the manipulation of the III stage of internal hemorrhoids. The hemorrhoid mass purple red or bright red, like strawberry, mucous membrane thin easy to bleed. 4, external hemorrhoids: often due to fecal dryness, fecal exertion after the anal margin of the external protrusion of the swelling, pain is obvious, localized for the round swelling, tenderness is obvious, subcutaneous violet-blue nodules, mostly thrombosed external hemorrhoids; anus skin repeated minor injuries and infections, the skin can be made red, swollen, heat, pain, skin folds enlarged formation of inflammatory external hemorrhoids; inflammation subsides, the remains of the skin into a cumbersome, for the connective tissue of external hemorrhoids, only the post-anal discomfort, not easy to clean or itching symptoms. The symptoms are not easy to clean or itching. 5.Tumor: Rectal adenoma, chorionic or papillary adenoma, melanoma, low rectal cancer, etc. can be dislodged out of anus with feces, accompanied by blood in stool and pus and blood in stool. Anal canal cancer can be painful and bleeding, and the swelling is cauliflower-like, often outside the anus.