Blood without stool is associated with constipation combined with hemorrhoids and upper gastrointestinal bleeding. Constipation and hemorrhoids often strike at the same time and can form a vicious cycle. When these two diseases strike at the same time, many patients will have blood during defecation, mainly because the nature of the feces is too dry and it is difficult to defecate, while the compression of the anal canal causes the perianal veins to rupture and bleed. Because the stool keeps accumulating in the rectum without being discharged, the condition of blood without stool may be formed. In a more serious state, upper gastrointestinal bleeding not only causes more bleeding, but also leads to hyperactive intestinal peristalsis, and the blood in the intestine will be discharged rapidly. Many people will affect their appetite during the illness and even stop food intake, so all that comes out during defecation is blood and no stool.