Blood in the stool is the most common early symptom of internal hemorrhoids, so the average person always treats blood in the stool as a hemorrhoid attack. Because of this misunderstanding, many people have blood in the stool tend to use a little treatment of hemorrhoids suppositories, the symptoms can mostly be improved. However, for middle-aged and elderly people, blood in the stool may be a danger signal of rectal cancer, must cause enough vigilance. Hemorrhoids are characterized by bleeding in the anus after defecation, the blood is bright red, not mixed with feces or the appearance of blood, and then dripping blood, or even see the jet-like bleeding, the bleeding stops on its own after defecation. Internal hemorrhoidal bleeding is generally intermittent, fecal dryness, fatigue, alcohol, over-eating stimulating food is often the cause of bleeding. A small number of patients due to long-term repeated hemorrhoidal bleeding, can occur severe anemia. Internal hemorrhoids are divided into four degrees, I degree: fresh blood in stool, hemorrhoids do not come off, bleeding stops after defecation; II degree: fresh blood in stool, accompanied by hemorrhoidal prolapse, self-contained after defecation; III degree: blood in stool decreases, internal hemorrhoids come off by straining or increasing intra-abdominal pressure, and need to be contained manually; IV degree: internal hemorrhoids come off and can not be contained. Rectal cancer manifests itself in changes of defecation habit or fecal character, most of which are increased frequency of stool, unshaped or thin stool, stool with blood and mucus. Sometimes constipation or diarrhea alternates with constipation, stool becomes thin. Pain in the middle and lower abdomen, the degree of severity varies, mostly hidden pain or distension. Pay attention to whether there are systemic symptoms such as greediness, emaciation, fatigue, edema, hypoproteinemia, etc. When tumor necrosis or secondary infection occurs, patients often have fever. Rectal cancer is one of the few diseases that can be prevented among cancer diseases. Prevention mainly includes two aspects: 1. Lifestyle habits: reduce the intake of high-protein and high-fat food. Drink less alcohol, keep a good and optimistic state of mind, and strengthen regular daily sports. 2.Discovering early lesions: disposable rectal and sigmoidoscopy can safely check the favorable areas of intestinal cancer without pre-laboratory tests, painless and no cross-infection. Benign lesions such as adenomas and polyps can be detected in time at the stage of adenoma and polyps, and only a very small surgery is needed to remove these time bombs. This test is done once every 3 to 5 years and does not cost much.