The phenomenon of uneven stool thickness may be bowel cancer, usually rectal cancer is more common. Uneven stool bleeding indicates that there is a mass in the intestinal cavity, and the mass in the intestinal cavity compresses the patient’s stool, resulting in thin stool or unformed stool. Generally, thin stools are more common in the rectum, but in other parts of the colon, such as the descending colon or transverse colon, patients usually do not have thin stools in the anal cavity, so it is recommended to perform anoscopy directly, because many rectal tumors can be palpated during anoscopy, or combined with colonoscopy, because there may be multiple primary tumors, not only in the rectum, but also in other parts of the colon. Tumors may occur not only in the rectum, but also in other parts of the colon.