Blood in the stool is very strong and is commonly due to the following causes. The first, bleeding hemorrhoids, is mostly fresh blood in the stool, blood in the stool or bleeding after the stool. The second type is bleeding from ulcerative colitis, which is often accompanied by pus and blood in the stool, abdominal pain, and recurrence of the disease, and weight loss in patients with long duration of the disease. The third type of bleeding is caused by intestinal tumors and is accompanied by a change in bowel habits or a change in the thickness of the stool. The fourth type of bleeding is caused by hematologic disorders, which mainly cause thrombocytopenia and coagulation disorders. The above is only a determination from the symptoms, and further clinical examination is needed to confirm the diagnosis.