Objective:To study the effect of arsenic trioxide(As2O3) combined with ginsenosidesRg3 on inhibiting theNCI-H1299 lung cancer cells and subsistence in nude mice bearing hepatoma. Methods:MTT method was used to measure the inhibition effect ofAs2O3 combinedRg3 onNCI-H1299 cells, and the proliferation inhibiting effect was observed via establishing the transplanted tumor modelin vitro.A total of40 tumor-bearing nude mice were randomly divided into normal saline group,As2O3,Rg3 andAs2O3+Rg3 group.Transplantation tumor model of lung cancer in nude mice was constructed, followed by injection of certain concentrations of normal saline, As2O3, ginseng saponinRg3 andAs2O3+Rg3 every day.The survival duration and the tumors size of the mice were recorded and theKaplan-Meier curve was made; microscopic observation of apoptosis of tumor cellsin vivo was done usingTUNEL staining.Results:After72 h of injection, inhibition rate of tumor cell in normal saline group,As2O3 group,Rg3 group andAs2O3+Rg3 group was(5.66±0.31)%,(65.58±4.75)%,(44.69±3.32)% and(82.67±5.43)%, respectively.Inhibition rate of tumor cell inAs2O3 group,Rg3 group andAs2O3+Rg3 group was significantly higher than that of normal saline group(P<0.01); inhibition rate of tumor cells ofAs2O3+Rg3 group was significantly higher than that of the two groups givenAs2O3 orRg3 alone(P<0.01).The tumor volume of As2O3 group,Rg3 group andAs2O3+Rg3 group shrank to(65.38±3.25)%,(77.68±3.43)% and(42.65±3.55)% of the original, tumor volume of saline group was1.21 times of the original size(P<0.01);Median survival of saline group,Rg3 group,As2O3 group were significantly shorter than that of As2O3+Rg3 group(P<0.01); co-ordinated intervention ability ofAs2O3+Rg3 onNCI-H1299 cell was significantly higher than that ofAs2O3 orRg3, separately.Conclusions:As2O3 combined with Rg3 can significantly inhibit proliferation ofNCI-H1299 cells in lung cancer, prolong survival of tumor-bearing nude mice, and promote tumor cell apoptosis, and have significant effect on lung cancer treatment.