There is no blood in the morning before the bowel movement, the last with blood but disappeared is due to the occurrence of blood in the stool, may be due to ulcerative colitis, hemorrhoids, rectal cancer, can also be seen in anal fissure, rectal polyps and other diseases. 1. Ulcerative colitis: patients with ulcerative colitis can cause ulceration of the mucous membrane in the colon in severe cases, resulting in bleeding and blood in the stool. Some patients also suffer from persistent abdominal pain, increased frequency of bowel movements and nausea. 2. Hemorrhoids: blood in the stool is also one of the common symptoms of hemorrhoids, which is mainly due to bleeding caused by the hemorrhoid surface ulceration during defecation. Patients also suffer from anal pain, anal itching, and formation of swelling in the anal area. 3. Rectal cancer: Patients with rectal cancer have no obvious symptoms in the early stage, and sometimes irregular blood in stool may occur. Some patients may also have diarrhea, constipation alternately and anal swelling. Anal fissure, rectal polyps and other diseases may also cause blood in stool.