The natural course of diverticulitis is usually mild and often requires only conservative treatment. The combination of pain in the lower left abdomen on physical examination, the absence of vomiting and a CRP > 50 mg/l is highly predictive of diverticulitis; further investigation by means of imaging may then be omitted. An initial ultrasound - and CT scanning only if this investigation proves negative or inconclusive - provides the best results in terms of imaging. There is no evidence substantiating the efficacy of routine antibiotic administration to patients with clinically mild and uncomplicated diverticulitis. Pericolic or pelvic abscesses can initially be treated with antibiotics, possibly in combination with percutaneous drainage; surgical intervention is only necessary if this treatment regimen fails. A patient with perforated diverticulitis resulting in peritonitis should undergo an operation; the optimal surgical strategy is currently under debate.