The reasons are usually age-based. Rectal polyps or colonic polyps are the most common causes of rectal bleeding in children . Hemorrhoids are one of the common causes of rectal bleeding. In addition there is anal fissure or rupture of the anus. In addition to this, one of the reasons for bleeding is rectum and colon cancer. These diseases are more common in middle age. In addition, if there is inflammation in the large intestine or if there is an infection in the large intestine , blood can pass through the rectum in middle age. The advice I give in this case is to drink enough water, eat certain amount of vegetables , you can also take the advice of an experienced doctor.