The first blood in stool on the fourth day after stoma retrieval surgery is related to anastomotic bleeding, anastomotic infection, anal disease and so on. 1. Anastomotic bleeding: when the anastomosis is not back to normal, the intestinal contents will easily rub the wound when passing through the anastomosis, resulting in blood seepage from the anastomosis and blood in stool. At this time, you can observe the wound for two days, and if the bleeding continues, you may need another surgery to close the wound. 2. Anastomosis infection: if in addition to bleeding in the stool, accompanied by fever, abdominal pain, abdominal distension, etc., the anastomosis may be infected, then you need to take antibiotics for treatment, such as ciprofloxacin and penicillin and so on. 3. Anal disease: due to the reduction of exercise after surgery, so there may be anal disease, such as internal hemorrhoids, its rupture can also appear in the stool with blood, at this time you can do colonoscopy, clear diagnosis. Blood in the stool for the first time on the fourth day after stoma retrieval surgery is also seen in other causes, it is recommended to visit the hospital in a timely manner, under the guidance of the doctor, so as not to delay the condition.