To explore the effect of clerodendrum bungei steud flavonoids (CBSF) on mice with Lewis lung cancer and its correlation to the expression of p53,bcl-2,and bax.Methods:To select 50 C57BL/6 male mice,after modelling,choose 40 with Lewis lung cancer and randomly divided them into four groups:model group,DDP group,CBSF high dose group,CBSF low dose group (with 10 in each),and 10 healthy mice into blank group.Drug administration:model group:intraperitoneal injection of physiological saline 0.01 mL/g for 14 days; DDP group:intraperitoneal injection of DDP 0.4 mg/kg for 5 days; CBSF high dose group:intraperitoneal injection of CBSF 0.6 g/kg for 14 days; CBSF low dose group:intraperitoneal injection of CBSF 0.3 g/kg for 14 days.Execute all mice after the medication,then weight up the tumors and calculate the tumor inhibition rate.Besides,using real-time PCR method to detect the expression of p53,bcl-2 and bax.Results:1)The effect on tumor weight(x-±s).The tumor weight of four groups are as follow:model group (4.70±1.29)g,DDP group (2.24±0.68)g,CBSF high dose group (3.26±1.06)g,CBSF low dose group (3.99±1.31)g.The tumor weight of DDP group and CBSF high dose group are lighter than that of the model group (P<0.05).Besides,there is no significant difference between these two groups (P>0.05).2)The tumor inhibition rate (IR).The IR of DDP group is 53.4%,CBSF high dose group is 30.6%,and CBSF high dose group is 15.1%.3)The effect on gene expression.Both CBSF groups can up-regulate the expression of p53 mRNA and bax mRNA (P<0.05 or P<0.01); DDP group can down-regulate the expression of bcl-2 mRNA (P<0.05) and up-regulate the expression of bax mRNA (P<0.01).Conclusion:Clerodendrum bungei flavonoids can improve the living quality of Lewis lung cancer mice and inhibit growth of tumor.Its antineoplastic mechanisms might be up-regulation of the expression of p53 mRNA and bax mRNA and induce apotosis of tumor.