Bowel cancer is a relatively common malignancy that includes mainly colon cancer and rectal cancer. The color of colon cancer blood in the stool is mainly related to the location of the lesion and is directly related to the time the blood remains in the body, i.e. the longer it remains and the higher the location, the darker the color of the blood. When the location of rectal cancer mass is relatively low, the stool will appear bright red, which needs to be distinguished from internal hemorrhoids, etc. Except for bright red stool, internal hemorrhoids usually have no pain, abdominal distension, change in bowel habit and other manifestations. The two can be distinguished by colonoscopy. When the mass is located high, the blood will mix with the stool when it bleeds, causing the stool to be mixed with blood and appear dark red. In addition, when local infection occurs, the stool will also contain pus. In short, the color of blood in the stool of bowel cancer is not entirely certain, and may vary from case to case, and is more closely related to the location of the lesion.