OBJECTIVE: To investigate the effect of Renshenwuweizi decoction(RSWWZ decoction) on the growth of non-small cell lung cancer cells in vitro.METHODS: A549 non-small cell lung cancer cells were divided into two groups: control and RSWWZ decoction treatment groups. Cell Counting Kit-8 was used to measure the inhibitory effect of RSWWZ decoction on the growth of A549 cells. 4', 6-diamidino-2-phenylindole staining and Annexin V-fluorescein isothiocyanate/propidium iodide double staining were used to investigate apoptosis in A549 cells following RSWWZ decoction treatment, and the mitochondrial membrane potential of treated cells was detected with Rhodamine 123. Cell cycle progression was analyzed by flow cytometry. The m RNA levels of p53, Bax, B-cell lymphoma-2(Bcl-2)and p21 were measured by quantitative real-time reverse transcription polymerase chain reaction.The protein expressions of p53, Bax, Bcl-2, p21, cyclin-dependent kinases 2(CDK2), and cyclin A were detected by Western blot.RESULTS: RSWWZ decoction reduced the viability of A549 cells in a dose-dependent manner by inducing apoptosis and decreased mitochondrial membrane potential. RSWWZ decoction increased p53 and Bax expression and decreased Bcl-2 expression in a dose-dependent manner. RSWWZ decoction also induced an S-phase cell cycle arrest by increasing p21 and decreasing cyclin A and CDK2 expression.CONCLUSION: In vitro experiments revealed that the Renshenwuweizi decoction-induced decrease in A549 cell proliferation was achieved by inducing apoptosis and S-phase cell cycle arrest via the p53 pathway. These findings provide the experimental basis for Renshenwuweizi decoction treatment of lung cancer.