To examine the effect of patient's age and the location of diverticular disease on the course of the acute disease we retrospectively collected demographic data, symptoms, laboratory findings, imaging techniques, type of treatment (conservative vs, surgical), early and late complications, and follow-up data on 119 patients with acute diverticulitis (74 women, 45 men, mean age 64 ± 14 years; follow-up 7-102 months, median 40). Patients were divided by their age into two groups (42 aged 60 years or younger, 77 aged over 60) and on the location of their disease (108 to the left of the middle transverse, 11 to the right). Lower abdominal pain, abdominal tenderness, and fever were the most common complaints (70-97%). In the younger patients we found a significantly greater preponderance in the right colon (P = 0.02) than in older patients. Abdominal abscesses and fistulas were more common in right-sided diverticulitis (P = 0.01). Patients with right-sided colon diverticulitis were treated surgically (82%) and on an emergency basis more often than patients with left-side colon diverticulitis (25%; P = 0.001). Older patients treated conservatively suffered more than younger patients (61% and 33% respectively; P = 0.04) from recurrent abdominal pain but not from recurrent, confirmed diverticulitis. Patients with right-sided diverticulitis treated conservatively suffered more from recurrent diverticulitis episodes than patients with left-sided diverticulitis (P = 0.05). Younger patients thus do not have a more aggressive form of diverticulitis than older patients. Patients with acute diverticulitis in the right colon are likely to be operated earlier and for mistaken diagnoses than patients with left-sided diverticulitis.