Abstract: OBJECTIVE To investigate the adjuvant effect and mechanisms of artesunate on gemcitabine-based chemotherapy in pancreatic cancer. METHODS MTT assay was performed to evaluate the effect of artesunate and different concentrations of gemcitabine on changing the cell viability of Capan-2. Western blot analysis was performed to detect the effect of artesunate and gemcitabine on changing the expression of FOXO1, Noxa, Bim, and release of cytochrome C and Smac/DIABLO from mitochondria and activation of caspase-9, caspase-3 in Capan-2 cells. Flow cytometry analysis was performed to detect the mitochondrial membrane potential(Δφ) and apoptosis of Capan-2. RESULTS Adjuvant therapy of artesunate significantly enhanced the killing activity of gemcitabine against pancreatic cancer in vitro. Artesunate significantly promoted the expression of FOXO1 in Capan-2. However, transfection with FOXO1 siRNA obviously suppressed the adjuvant effect of artesunate on gemcitabine. Combination with gemcitabine and artesunate significantly induced the overexpression of Noxa and Bim, release of cytochrome C and Smac/DIABLO, activation of caspase-9 and caspase-3, suppression of Δφ and occurrence of cell apoptosis in Capan-2 cells. On the other hand, transfection with FOXO1 siRNA obviously suppressed the apoptotic pathway induced by the combination treatment with artesunate and gemcitabine in the Capan-2 cells. CONCLUSION Artesunate enhances the activity of gemcitabine on inducing the apoptosis of pancreatic cancer through the upregulation of FOXO1.