Diverticular disease in the colon. Endoscope view of diverticular disease (diverticulosis) affecting the sigmoid colon. Diverticulosis causes sacs (diverticula) to form and protrude externally from the colon wall. These can become inflamed, infected, and may rupture (diverticulitis). Treatment requires antibiotic drugs. More severe cases may require surgery to remove part of the colon. This is the sigmoid section of the colon, the part of the large intestine that is closest to the rectum and anus.