With the accelerated pace of people’s lives, the increase in the pressure of life and the continuation of bad eating habits, the middle and lower gastrointestinal bleeding is currently increasing, analyze the main causes are: 1, anal canal disease: mixed hemorrhoids, anal fissure, anal fistula. 2, rectal diseases: ulcerative proctitis, tumors (polyps), carcinoid tumors, adjacent malignant tumors or abscesses invading the rectum, infections (bacterial, tuberculosis, fungal, viral, parasitic), ischemia, etc. 3, colon disease infections: (bacterial, tuberculosis, fungal, viral, parasitic), ulcerative colitis, diverticula, tumors (polyps), ischemia and vascular malformations, intestinal loops, etc. 4, small intestine disease acute hemorrhagic necrotizing enterocolitis, intestinal tuberculosis, Crohn’s disease, diverticulitis or ulcer, intestinal overlap, tumor (polyps), hemangioma, vascular malformation, ischemia, etc. The above symptoms mostly need to be diagnosed and treated by specialists, so do not ignore them blindly. Different diseases are treated in different ways. It must be regular and scientific diagnosis and treatment.