Bowel cancer is a very common malignant tumor of the digestive system, which may show abnormal stool, such as bleeding in the stool, most of which is dark red, some of which may be black, and of course, some yellow stool, so bowel cancer stool may be not only two colors, but possibly three colors. For one patient, it may be one color or two colors. The diagnosis of bowel cancer cannot be fully made by the stool condition alone, and it needs to be confirmed by anal finger examination and colonoscopy, through which pathology can be taken. After the diagnosis of bowel cancer is confirmed, surgery is the main treatment if it is possible, and post-surgery is combined with adjuvant radiotherapy, chemotherapy and other comprehensive treatments, some of which can also be considered as targeted drugs and other treatments. After surgery, it is necessary to observe the stool condition to help understand whether there is any recurrence of the disease. For example, the sudden appearance of blood in stool or persistent black stool after surgery indicates that the disease may have progressed and further examination is needed.