Bright red blood may be caused by rectal polyps, hemorrhoids, ulcerative colitis, anal fissure and other reasons. 1. Rectal polyps: Rectal polyps are usually caused by heredity, ageing, inflammatory stimuli, etc. When the surface of the patient’s polyp ulcerates, bright red blood can appear in the stool. 2. Hemorrhoids: hemorrhoids, especially internal hemorrhoids, mixed hemorrhoids, the main symptoms of bleeding and hemorrhoidal prolapse, blood is bright red, more at the end of defecation covered in the surface of the stool, the most common is still intermittent blood after stool. 3. ulcerative colitis: ulcerative colitis is more serious patients, sometimes the bleeding location close to the rectum and the amount of bleeding will appear when the symptoms of fresh blood after the stool bright red. 4. anal fissure: anal fissure patients will appear in the case of blood in the stool, the color is mostly bright red, but the amount is generally less, mostly attached to the surface of the stool or toilet paper with fresh blood, accompanied by obvious anal pain. If there is a case of pulling blood bright red, there may also be rectal cancer, coagulation dysfunction and other diseases, so you should go to the hospital in time to improve the examination, diagnosis and treatment under the guidance of the doctor, so as not to miss the condition.