There are many reasons for blood in stool one year after colon cancer surgery, such as bleeding of internal hemorrhoids, anal fissure or recurrence of colon cancer may cause blood in stool, patients should consult doctor in time and take corresponding treatment according to doctor’s advice. The most common cause of blood in stool is bleeding internal hemorrhoids, which mostly occurs during constipation or diarrhea, and is easy to occur after drinking alcohol or eating spicy food. Secondly, the cause of blood in stool may be anal fissure. Patients with blood in stool are usually accompanied by anal pain during defecation, which can be treated by using drugs such as Ma Ying Long Hemorrhoidal Cream. Colon cancer mainly exists in the intestinal tubes, and its surface is very fragile and easily irritated by intestinal contents, which may rupture and lead to bleeding. If there is bleeding in stool one year after colon cancer surgery and the bleeding is serious, patients should go to hospital for examination and treatment in time.