Bleeding from the stool in bright red color, vague pain in the stomach, back pain may be caused by colonic lesions such as ulcerative colitis, colorectal cancer, colorectal polyps, etc., or due to anorectal diseases, such as hemorrhoids, anal fissure, anal fistula and other diseases. Bleeding is bright red, indicating that the bleeding is not far from the anus and is usually located within the rectum to the descending colon. Colon lesions are common: 1. Ulcerative colitis: initially, it manifests as bloody diarrhea, and some patients also have abdominal pain, lumbar pain and blood in stool. 2. Colorectal cancer: lumbar peritoneal or lumbar spine metastasis may occur and lumbar and abdominal pain may occur, meanwhile, the surface of cancer tumor in intestine is easy to appear mucous membrane damage or erosion and bleeding, so there will often be bleeding in stool, bright red tummy hidden pain and lumbar pain. 3. Colorectal polyp: refers to the proliferation of rectal mucosa surface protruding into the intestinal lumen, mainly manifested as bright red blood in stool, when accompanied by other lesions in the abdominal cavity, there will also be bleeding in stool, bright red tummy hidden pain, low back pain and other manifestations. Anal and intestinal diseases such as hemorrhoids, anal fissure, anal fistula, etc. can appear in the stool bleeding bright red, there may be hidden pain in the stomach or back pain. Patients with such symptoms, should go to the hospital in time for relevant examinations, clear diagnosis and follow the doctor’s instructions for treatment.