The treatment of aortic regurgitation (AR) caused by cardiovascular Behçet's disease was retrospectively analyzed in five patients with Behçet's disease complicated by moderate or severe AR (four men and one woman, with a mean age of 47 +/- 5.8 years; complete 1, incomplete 2, and suspected 2). The preoperative left ventricular end-diastolic diameter was larger than 60 mm (mean: 74 mm) in all patients, and the left ventricular fractional shortening was less than 0.28 in three patients. Aortic valve replacement (AVR) was performed in four patients, but perivalvular regurgitation developed in all patients after a mean of 5.4 +/- 1.2 months (range: 0.6-10 months) following surgery, causing the death of three patients. One patient (grade III) who did not undergo operation showed gradually increasing end-diastolic diameter, but he is still being followed up medically due to the poor outcome of surgery. Because of inflammation-induced tissue fragility, AVR was associated with postoperative perivalvular regurgitation and suture breakdown, resulting in an extremely poor outcome. Thus, AVR was considered best avoided even if Behçet's disease was complicated with moderate or severe AR.