There are four causes of red blood in the stool: The first condition, hemorrhoids. This is usually seen when there is blood dripping from the stool or blood on the hand paper, often accompanied by a feeling of anal swelling, and requires a finger anal examination to clarify. The second condition, anal fissure. This can be seen as a painful tearing in the anus when relieving stool, and can also be clarified by finger-anal examination. The third condition is rectal and sigmoid colitis, tumors, polyps, etc., which can be clarified by colonoscopy. The fourth condition is seen in systemic diseases, such as abnormal coagulation function, which is often accompanied by bruising and petechiae on the body surface, and requires a coagulation test to clarify.