Diverticular bleeding is a condition in which pouches (diverticula) that have formed in the wall of the large intestine (colon) bleed. Bleeding into the colon occurs when the blood vessel going to the pouch breaks open.
Sometimes a person with diverticular bleeding will have sudden, severe bleeding from the rectum. Bleeding often will stop on its own. If it does not, treatment may be needed to stop the bleeding and to replace lost blood.