Diverticulosis is a condition in which pouches called diverticula form in the wall of the large intestine (colon). The pouches may not cause any symptoms, or they may bleed or become painful, inflamed, or infected.

The reason pouches (diverticula) form in the colon wall is not completely understood. Doctors think diverticula form when high pressure inside the colon pushes against weak spots in the colon wall. These pouches are usually very small (5 to 10 millimetres) in diameter but can be larger. They become more likely with age. They are found most often in the colon. But diverticula can be found in nearly all parts of the digestive tract.

Most people don't know they have diverticulosis. If diverticulosis isn't causing any problems, it may not need to be treated. If diagnosed, it is usually managed by increasing the amount of fibre in the person's diet and avoiding constipation.