Over the last 100 years, the prevalence and incidence of diverticulosis and diverticular disease have increased dramatically in western industrialized countries. The main reasons for this are considered to be changes in eating habits, and the increasing age of the population. Conservative treatment of diverticulitis is an initial period of fasting and antibiotic treatment. For recurrence prevention, a fiber-rich diet is recommended. Studies providing evidence in support of the general recommendation of recurrence prophylaxis with poorly absorbed antibiotics, mesalazine or probiotics are to date not adequate. Elective prophylactic sigmoid resection is to be recommended following an episode of diverticulitis with complications, and after an episode of uncomplicated diverticulitis in long-term immunosuppressed patients who have already had an attack. Elective sigmoid resection after a healed second attack of uncomplicated diverticulitis is controversial.