A retrospective study of 310 patients from 1978 to 87 showed emergency operations for peritonitis, acute obstruction (5%) and massive hemorrhage (3%) in 22% of the patients and various procedures for abscesses, such as delayed emergency in 14% and elective resections in 41%. Conservative treatment was given to 23% of patients with acute diverticulitis without further symptoms. During followup 68% had no symptoms, while 7% required resection for complications. The death rate for diffuse peritonitis has fallen: from 33 to 16% with Hartmann operation, and for perforations without and with abscesses from 4 to 0% and 12 to 4%, and from 1.2 to 0.6% in elective primary resection.