Bleeding in stool is not necessarily a symptom of bowel cancer, nor does bowel cancer necessarily have bleeding in stool. Many other diseases can also cause bleeding in stool, such as hemorrhoid bleeding, usually blood in stool, or blood dripping after stool, and itching in anus; ulcerative colitis, mainly pus and blood in stool, and abdominal pain and weight loss; blood in stool can also occur in blood system diseases. Only when the tumor damages blood vessels and causes bleeding, it will lead to blood in stool. For many bowel cancers, if the tumor does not damage the blood vessels, the symptoms of blood in stool will not appear. Therefore, for bleeding in stool, further examination of its cause is needed.