Diverticulitis is a complication to the common condition diverticulosis. Uncomplicated diverticulitis has traditionally been treated with antibiotics. Risk factors for diverticulitis, however, may suggest, that the condition is inflammatory rather than infectious. The evidence on antibiotic treatment for uncomplicated acute diverticulitis suggests, that antibiotics have no effect on complications, emergency surgery, recurrence, elective colonic resections and long-term complications. The evidence is based on three randomised clinical trials on the need for antibiotics, which is summarised in this review.