The reason for bright red blood in the stool and not mixed with feces, mainly considered to be the anorectal related diseases, generally suggesting hemorrhoids, anal fissures, anal polyps, rectal prolapse, rectal cancer, etc., when the relevant symptoms suggest timely medical treatment, so as not to delay the disease. 1, hemorrhoids: hemorrhoids is the bottom of the anorectum and the anal mucosa of the venous plexus, the formation of varicose and one or more soft venous masses. It is a chronic disease. The most common clinical symptom is blood in the stool, the color of the bleeding is usually bright red and the bleeding is characterized by blood in the stool, dripping blood after the stool, jet bleeding or blood on the hand paper. Generally asymptomatic hemorrhoids do not require treatment, if frequent bleeding, then sclerotherapy or surgery can be performed; 2, anal fissure: anal fissure is a chronic non-specific longitudinal ulcer in the epithelium of the anal canal, often radial, shaped like a pike or oval, mainly manifested as severe pain in the anus, so much so that some patients do not dare to defecate. When defecating, a small amount of blood is often seen on the surface of the stool or on the stool paper, which is usually treated clinically by means of sitz bath and moistening the stool; 3. Anal polyps: If polyps appear in the anal canal or rectal mucosa due to diet, inflammatory stimulation, long-term constipation, etc., squeezing the polyps when the patient defecates may lead to bleeding, and the blood is often bright red and can be attached to the surface of the stool. Patients can go to the hospital to surgically remove polyps to completely cure; 4, rectal prolapse: is due to constipation, diarrhea and other reasons resulting in increased abdominal pressure, rectal wall part or full layer downward displacement, prolapsed rectal mucosa may occur inflammation, erosion, ulcers and other symptoms, and then bright red blood stool. It is recommended that patients reset the prolapsed rectum immediately after defecation and actively treat the primary diseases that cause increased abdominal pressure; 5, rectal cancer: malignant tumors originating from the rectal mucosal epithelium, due to the extrusion of the tumor during defecation, can lead to bleeding during defecation, bright red or dark red blood, dripping and attached to the surface of the stool, can be accompanied by mucus, and when complicated by serious infection, can appear pus and blood stool. In the late stage, it may be accompanied by anal cramping, generalized weight loss, increased frequency of stool, and alternating constipation and diarrhea.