Diverticulosis is the presence of weak areas or pouches in the wall of the large intestine.
The pouches are usually in the part of the intestine called the colon. The pouches, called diverticula, look somewhat like small thumbs poking out of the side of the colon. Diverticulosis is a common condition. More than half of all elderly people in the U.S. have it. Diverticula seem to occur when the pressure inside the colon is too high.