Bleeding in stool with normal colonoscopy can be caused by anal canal diseases such as hemorrhoids and anal fissure. Bleeding in the stool is defined as bleeding in the digestive tract, where blood is expelled from the anus; it can be seen in a variety of diseases, such as upper gastrointestinal bleeding, middle gastrointestinal bleeding, lower gastrointestinal bleeding, and systemic diseases; lower gastrointestinal diseases can be divided into colon diseases, rectal-anal tube diseases, and vascular diseases. Hemorrhoids, anal fissure patients with blood in the stool is bright red in color, the lesion is located in the anal canal; colonoscopy can not detect this part of the anal canal; therefore, the symptoms of bleeding in the stool can occur while the colonoscopy is normal. For hemorrhoids patients, the main non-surgical treatment, change bad bowel habits, hot water sitz bath to improve blood circulation, etc.; anal fissure patients in addition to bleeding in the stool, there is severe pain; can be used in sitz baths, laxative laxative treatment; treatment is ineffective, it is recommended to go to the hospital in a timely manner to consult a doctor for treatment.