Anal distension and constant urge to pass stool may be caused by constipation, hemorrhoids, perianal abscess, proctitis, anal polyps or tumors, rectal mucosal prolapse and other factors. 1. Constipation: It may be related to endocrine abnormalities, improper diet and other factors, which will cause constipation, and there will be a constant urge to poop, anal swelling, but it is difficult to discharge the stool. 2. Hemorrhoids: may be related to poor dietary habits, poor defecation habits and other factors, will make the patient frequently have the urge to defecate, and accompanied by a feeling of anal swelling, but also accompanied by anal itching, pain, bleeding and other symptoms. 3. Perianal abscess: it may be related to prolonged constipation, anal injury, infection and other factors, which may lead to anal swelling and frequent urge to have stool, accompanied by anal itching, pain, rectal bleeding and other symptoms. 4. Proctitis: it may be related to dietary factors, mental and psychological factors, genetics and other factors, which can lead to frequent bowel movements, and there is a feeling of anal swelling, accompanied by rectal bleeding, diarrhea, pain and other symptoms of defecation. 5. Anal polyps or tumors: when there are anal polyps and tumors, it will affect the normal defecation, and there will be difficulty in defecation, constant urge to defecate and anal swelling. It may also be accompanied by blood in stool, diarrhea and other symptoms. 6. Prolapse of rectal mucosa: it may be related to the change of rectal mucosa, neurological hypoplasia and other factors, which may make the patient bleed frequently, and accompanied by abdominal distension, difficulty in defecation, pain in defecation and other symptoms. The anal part of the swelling of the old urge to defecate, it is recommended to seek medical treatment for the appropriate examination and treatment, to avoid delays in the condition.