AIM To evaluate systematically our nine-year experiencein treating right-sided diverticulitis of the colon,and toexplore its clinical and radiological relationship.METHODS:The clinical and radiological data of 40 patientswith colonic diverticulitis treated in Mackay Memorial Hospital,Taipei,from 1993 through 2002 were reviewed retrospectively.RESULTS:The average age of the patients with right-sideddiverticulitis was 53.1 years,which was 11.6 years youngerthan that of the patients with left-sided diverticulitis.Thepreoperative diagnosis of appendicitis was made in 8 of 13right-sided diverticulitis patients.Nine(69 %)had right lowerquadrant abdominal pain for more than 48 hours,and tenpatients(77 %)presented with fever.CT findings suggestingacute right-sided diverticulitis including thickening of theintestinal wall and pericolonic inflammation were present infive patients.CONCLUSION:Right-sided diverticulitis is easily confusedwith acute appendicitis because it occurs at a somewhatyounger age than that in left-sided diverticulitis.Bariumenema and CT are helpful for the early diagnosis of right-sided diverticulitis.While clearly not required in the majorityof patients with right lower quadrant abdominal pain,bariumenema and CT may be helpful in making the decision with aclinical history or physical examinations atypical of acuteappendicitis. AIM To evaluate systematically our nine-year experience in treating right-sided diverticulitis of the colon, and to explore its clinical and radiological relationship. METHODS: The clinical and radiological data of 40 patients with colonic diverticulitis treated in Mackay Memorial Hospital, Taipei, from 1993 through 2002 were reviewed retrospectively .RESULTS: The average age of the patients with right-sided diverticulitis was 53.1 years, which was 11.6 years youngerthan that of the patients with left-sided diverticulitis. This preoperative diagnosis of appendicitis was made in 8 of 13 right-sided diverticulitis patients. Nine (69%) had right lower quadrant abdominal pain for more than 48 hours, and tenpatients (77%) presented with fever. CT findings suggesting acute right-sided diverticulitis including thickening of the intestinal wall and pericolonic inflammation were present infive patients. CONCLUSION: Right- sided diverticulitis is easily confusedwith acute appendicitis because it occurs at somewhatyounge r age than that in left-sided diverticulitis.Bariumenema and CT are helpful for the early diagnosis of right-sided diverticulitis. Whilst clearly not required in the majority of patients with right lower quadrant abdominal pain, bariumenema and CT may be helpful in making the decision with aclinical history or physical examinations atypical of acuteappendicitis.