any small pouch or sac that forms in the wall of a major organ of the human body. Diverticula form most commonly in the esophagus, small intestine, and large intestine and are most often a problem in the latter organ. Middle-aged and older people are particularly susceptible to the condition because of the inevitable weakening of the muscle walls of the colon with advancing age.

Fecal matter may be pushed into the pouches that form in the colon and may cause them to bulge out from the colon wall. Such a condition is called diverticulosis. Diverticulosis occurs in 5 to 10 percent of persons over 40 years of age; its cause is unknown, but weakness of the intestinal wall and increased pressure within the channel of the intestine are probably significant factors. Diverticulosis has no symptoms, but the feces-filled sacs may become infected or inflamed, progressing to a more serious condition called diverticulitis. Its symptoms are pain and tenderness in the lower left side of the abdomen, chills, and sometimes fever. The presence of diverticulitis can be determined by X rays or computed tomography (CT) scans. The treatment for a mild or moderate case of diverticulitis consists of bed rest, antibiotics, and a liquid diet. A severe case can result in perforation, rupture, ulceration, or hemorrhaging of the colon wall at the site of the diverticulum. In cases of perforation, the surgical removal of portions of the colon, known as a colostomy, may be necessary.