Bleeding from internal hemorrhoids, also known as rectal bleeding, is the most common primary clinical manifestation in patients with internal hemorrhoids. Internal hemorrhoids refer to the venous clusters that grow above the dentate line, and their onset occurs above this line. The area above the dentate line is mainly controlled by the autonomic nervous system, making it insensitive to pain and irritation. Therefore, many patients with bleeding internal hemorrhoids may not even realize it themselves, as it does not cause pain. In contrast, external and mixed hemorrhoids, which involve the area below the dentate line, are controlled by somatic nerves, making pain more readily felt.