In order to study effects of ginseng on the metabolism of drug belong to CYP3A4 substrate, screening of pregnane X receptor activation from ginsenosides was performed by reporter assay.  Based on PXR-CYP3A stable translation cell lines, 13 ginsenosides were screened for pregnane X receptor activation by reporter assays, and RIF as the positive control.  The effect of ginsenosides Rg1 on CYP3A4 mRNA expression was also investigated by RT-PCR.  The PXR-CYP3A stable translation cell lines had good response to RIF, and the EC₅₀ is 2.51 μmol·L⁻¹.  When the condition of final concentration was 10 μmol·L⁻¹, ginsenoside F2 and protopanaxatriol had moderate inductive effects on PXR.  Panaxotriol, Rg2, pseudoginsenoside F11, Rg1, ginsenoside and Rb3 had inhibitory effects on PXR.  Ginsenoside Rf1, Rg3, Rh2 and protopanaxdiol had no obvious effects on PXR.  Rg1 down-regulated CYP3A4 mRNA expression in a concentration-dependent manner.  Activation of pregnane X receptor by ginsenosides may influence the metabolism of drug belong to CYP3A4 substrate, and cause ginseng-drug interactions.