Acute diverticulitis is inflammation due to micro-perforation of a diverticulum. The diverticulum is a sac-like protrusion of the colon wall. Diverticulitis can present in about 10% to 25% of patients with diverticulosis. Diverticulitis can be simple or uncomplicated and complicated. Uncomplicated diverticulitis is without any associated complications. Complicated diverticulitis is associated with the formation of abscess, fistula, bowel obstruction, or frank perforation. Diverticulitis has conventionally been known and treated as a primarily surgical illness, but this has transitioned to be a medically managed entity even in its most acute phase.