Objective To explore the role of 1, 4, 5-trisphosphate inositol ( IP3) and bax gene expression in apoptosis of HepG2 cells induced by Quercetin.Methods HepG2 cells were cultured for 72h as control. HepG2 cells were treated with different concentrations including 20,40.60,80?mol/L Quercetin for 72h, and treated with 60?mol/ L Quercetin for 12h, 24h, 48h and 72h. IP3, bax mRNA, bax protein and apoptosis rate were assayed by IP3-[3H] Birtrak assay,RT-PCR, Western blotting and flow cytometry, respectively.Results In HepG2 cells incubated with each of the concentrations of Quercetin for 72 h,IP3continent was lower than that of control(P