Bleeding from the stool that is bright red in color and accompanied by pain is mainly caused by proximal anal injuries accompanied by active bleeding. Common causes of this condition include hemorrhoids, anal fissures, active colitis, and perianal mucosal injuries. 1. Hemorrhoids: mainly external hemorrhoids or mixed hemorrhoids after scratching, will cause pain, most of the manifestations of bright red blood after the stool. 2. Anal fissure: prolonged constipation, trauma and other causes of perianal skin tearing, which will lead to pain during defecation with the appearance of red blood. 3. Active colitis: common as ulcerative colitis, inflammation will lead to mucosal edema, shedding, capillary rupture caused by bleeding, abdominal pain and other manifestations. If the bleeding point is close to the anorectum and the amount of bleeding is large, the color of blood can be bright red. 4. Perianal mucous membrane injury: excessive defecation, perianal mucous membrane repeated irritation, scratches will cause related symptoms, will be accompanied by peripheral redness, swelling and oozing. Bleeding in stool with bright red color and pain may also be caused by other diseases such as rectal cancer, so it is necessary to consult a doctor in time and carry out standardized treatment under the guidance of clinicians.