Bleeding in the stool after heart bypass surgery can be caused by anticoagulant drugs or gastrointestinal diseases. 1. Anticoagulant therapy is routinely administered before and after cardiac bypass surgery. The effect of anticoagulant therapy is to decrease the body’s clotting function, and if there is a bleeding point in the gastrointestinal tract, such as hemorrhoids or other disorders, bleeding in the stool will occur. The main treatment is to consult the attending physician, stop using anticoagulant drugs, and find out the location of the bleeding and related treatment. 2. Then there may be gastrointestinal diseases that aggravate bleeding, such as gastroduodenal ulcer bleeding due to the stress of surgery or psychological factors, or hemorrhoid bleeding. It is recommended to go to the hospital immediately and follow the doctor’s instructions for treatment. Bleeding in the stool should be timely medical treatment, timely identification of the cause of the disease to be treated, so as not to delay the disease.