Large amount of blood in stool without pain is not necessarily bowel cancer, but may also be hemorrhoids, gastrointestinal ulcers, coagulation dysfunction, etc., which needs to be judged according to its accompanying symptoms. If accompanied by constipation, anal swelling and other symptoms, the bleeding is bright red, usually caused by hemorrhoids. If it is dark red bloody stool or thin paste-like tarry stool, it may be caused by gastrointestinal ulcer, acute gastric mucous membrane lesion, etc. If accompanied by generalized petechiae, ecchymosis or bleeding gums, etc., it may be due to blood clotting disorder. If the patient develops intestinal cancer, in addition to blood in stool, there will be a dull pain in the abdomen, similar to the feeling of a fist hitting the stomach, mucous bloody stool or mucous pus and blood stool, and a lump with hard texture and inconspicuous boundary can be felt in the abdomen. If there is a large amount of bleeding during bowel movement without pain, you can consult the anorectal department, gastroenterology department or hematology department, etc., according to its accompanying symptoms.