The aim of the present study was to evaluate whether antibiotics is mandatory for the treatment of acute uncomplicated right-sided diverticulitis.

The hypothesis is that patients having acute uncomplicated diverticulitis at right-sided colon will be recovered without antibiotics.

All patients in the study were randomly allocated to one of the following two treatment groups; no-antibiotics group or antibiotics group.

Patients of no-antibiotics group were admitted to the ward and administered intravenous fluid and bowel rest at least up to 5 days until clinical symptom and sign were stabilized. And then the patient discharge until oral intake was tolerated.

In antibiotics group, the treatment was initiated with an intravenous combination of a third generation cephalosporin or quinolone and metronidazole until oral intake was tolerated. Oral antibiotics such as cefpodoxime together with metronidazole were initiated subsequently on the ward. The total duration of antibiotic treatment was an expected average 10days.

Patients in both group were re-visited outpatient clinic after an expected average 7 days for check-up of serology test (including complete blood count and C-reactive protein), and after an expected average 6 weeks for CT. If the patients did not re-visit outpatient clinic, we checked the call.

Inclusion Criteria:

• Right-sided colonic diverticulitis
• Uncomplicated diverticulitis

Exclusion Criteria:

• Pregnancy
• Refuse to investigation
• Immunosuppressive therapy or immunologic incompetence
• Colonic diverticulitis except right-sided diverticulitis
• Complicated diverticulitis
• Disorder of psychology or cognition
• Allergic reaction to antibiotics being used in the study (3rd generation cephalosporin, quinolone, metronidazole)