Abstract: Objective :To explore the inhibitory effects of Triptolide (TL) on the growth and angio-genesis of transplanted human pancreatic tumors in nude mice. Methods :Different dosages of TL wereadministered to nude mice that were injected with SW1990 cells. The inhibitory effects on the growth oftumor xenografts and tumor microvascular density (MVD) were investigated. VEGF protein and mRNAexpression were detected by immunohistochemistry and semi-quantitative RT-PCR. Results :TL signif-icantly suppressed the growth of tumor when administered at 0.125, 0.25 and 0.5 mg/kg·day, and theinhibitory rate was 66.16%, 78.14% and 89.92%, respectively. The control group showed the highestMVD level of 36.25±8.64, while the 0.5 mg /kg·day TL group displayed the lowest level of 9.87±3.34.TL caused a dose-and time-dependent inhibitory effect on VEGF protein and mRNA expression. Apositive correlation was found between VEGF expression and MVD in the tumors (r=0.742 4, P<0.01). Conclusion :The inhibitory effects of TL on transplanted human pancreatic tumor cells in nude micemay partially be due to its antiangiogenic activity. TL should be examined further as a novel anti-neo-plastic agent for the treatment of pancreatic tumors.