Abstract: OBJECTIVE To investigate the role and mechanism of ligustrazine in mice liver drug metabolism enzyme Cyp3a11 (CYP3A4 homologous gene). METHODS Eight-week-old male C57BL/6 mice were treated oridonin orally (0, 25, 50, 100 mg·kg^-1, i.g.) for 15 d. The effects of oridonin on Cyp3a11 in mice livers were examined at both the mRNA and enzyme activity levels, which detected by RT-PCR and HPLC-MS/MS respectively. Finally, the effect of ligustrazine on the transcription activity of CYP3A4 was analyzed by luciferase reporter gene assays. RESULTS Ligustrazine could induce the mRNA expression of Cyp3a11 in mice and the induction were dose-dependently. At the same time, the liver microsomal activity experiment showed that the metabolic activity of Cyp3a11 was increased in high dose group. The results showed of luciferase reporter gene assays that ligustrazine activated CYP3A4 promoter transcriptional activity through nuclear receptor PXR pathway. CONCLUSION Ligustrazine could induce the expression and activity of Cyp3a11, homologous gene of CYP3A4. Since ligustrazine is usually co-administered with other clinical medicine, the present study may provide at least part of the basis for drug-drug interactions.