Blood in stool after colon cancer surgery may be a normal phenomenon, or it may be caused by insufficient hemostasis, tumor recurrence and other factors, which need to be specifically examined and analyzed. 1. Normal phenomenon: a small amount of blood in stool at the early stage of postoperative period, other clinical symptoms are light, and the amount of bleeding gradually decreases, which may be a normal phenomenon. 2. Inadequate hemostasis: Inadequate hemostasis during surgery or detachment of ligature wire may lead to postoperative blood in stool, which may increase in volume and be accompanied by mild pain, and the doctor should be informed in time. 3. Tumor recurrence: if blood in stool occurs for a long time after surgery, one should be alerted to tumor recurrence, which is similar to the blood in stool of primary tumor, and the bleeding will persist and the amount of bleeding will increase. If there is blood in stool after operation for colon cancer and accompanied by other obvious abnormalities, it is recommended to consult doctor for examination and timely treatment after clarifying the causative factors.