The following are some of the possibilities: 1. Patients may suffer from severe internal hemorrhoids, which can cause blood in the stool and sometimes anal pain. 2. Ulcerative lesions in the rectum or proximal colon can cause blood in the stool, such as common ulcerative colitis, which sometimes discharges bloody fluid and much blood. 3. 4.Colon diseases can also cause blood in the anus, such as ulcerative colitis and dysentery. 5.Some patients with small intestine diseases that cause bleeding in the small intestine will also have blood in the stool, such as small intestine tumors, intestinal tuberculosis, necrotizing enterocolitis, intestinal overlap, etc. When the phenomenon of blood in the stool, to go to the hospital in a timely manner, you can carry out electronic colonoscopy to determine the cause of the disease.