Objective To observe the inhibition effect of 5-FU on tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)-induced apoptosis in gastric cancer BGC823 cells,and identify the action of death receptor 5(DR5) in 5-FU and TRAIL-induced apoptosis.Methods Cell proliferation was measured using MTT assay.Cell apoptosis was determined by flow cytometry.Expression of protein was analyzed by western blot.Results Treatment with 100 ng/mL TRAIL for 48 h slightly resulted in the inhibition of cell proliferation and a little cell apoptosis in BGC823 cells.Treatment with TRAIL(100 ng/mL) and 5-FU(5.55 g/mL,IC50 dose of 48 h) leaded to a dramatic increase in the inhibitiong of cell proliferation and cell apoptosis compared to treatment with 5-FU or TRAIL alone(P0.05).TRAIL alone did not change the expression of DR5,while 5.55 g/mL 5-FU significantly upregulated the expressions of DR5 in BGC823 cells after 48 h(P0.05).Treatment with 5-FU and TRAIL also resulted in the upregulation of DR5(all P0.05).Conclusion 5-FU enhance TRAIL-induced apoptosis in gastric cancer BGC823 cells by the upregulation of DR5.