There are many reasons for bleeding in the stool, such as common hemorrhoids, but also see anal fissures, rectal polyps, enteritis, and even colorectal cancer. If the blood in stool is fresh blood dripping after stool, it should be considered as possible hemorrhoids, blood in stool with constipation and painful defecation should be considered as possible anal fissure, diarrhea with blood in stool should be considered as possible enteritis, and if the stool is accompanied by mucus, increased frequency of defecation, abdominal pain and bloating, it should be closely suspected whether there is colorectal tumor. Firstly, anal finger examination should be used to exclude low rectal lesions. Anoscopy can detect hemorrhoids, anal fissures and rectal tumors. Positive stool occult blood test. If the blood carcinoembryonic antigen is elevated, colonoscopy is highly recommended to rule out colorectal tumors.