Diverticulitis is suspected when the patient has pain and tenderness on palpation on the lower left abdomen, fever and an elevated CRP level. After a confirmed diagnosis, outpatient therapy of uncomplicated diverticulitis is possible, according to the latest research results even without antimicrobial drugs. CT scanning is usually unnecessary when the CRP level remains below 50 mg/l in the absence of signs of peritoneal irritation, but should always be performed when the value exceeds 150 mg/l. Unenhanced CT scan without contrast agent is well suited for the exclusion of complicated diverticulitis.