Background/Aims: Gastrointestinal lesions of Behçet's disease (BD) are often refractory to medical therapy and sometimes result in serious comorbidities such as gastrointestinal perforation and massive bleeding. There are several reports of patients with BD comorbid with myelodysplastic syndrome (MDS) involving trisomy 8 that frequently have intestinal lesions refractory to conventional medical therapy. Little is known about the efficacy of infliximab (IFX) for these intestinal lesions. Methods: We present 2 cases of intestinal BD with MDS involving trisomy 8 who did not respond to IFX, and review previous reports of BD with MDS involving trisomy 8 concerning their responsiveness to conventional medical therapy. Results: Among 31 previously reported cases that received medical treatment for BD, 19 (61.3%) showed temporary improvement of the BD symptoms, 9 (29.0%) deteriorated, and 3 (9.7%) showed no change. All of the 9 cases that showed deterioration had intestinal lesions. Our 2 cases failed to respond to IFX, resulting in a poor prognosis. Conclusions: IFX might not be effective for improving intestinal BD comorbid with MDS involving trisomy 8. Trisomy 8 is associated with the BD prognosis and refractoriness to conventional medical therapy.