Abstract: AIM: To investigate the effects of Glycyrrhiza uralensis decoction on liver cytochrome P450 in rats.METHODS: SD rats were randomly divided into four groups (control, enzyme inducer, enzyme inhibitor and Glycyrrhiza uralensis decoction groups) and drugs were administrated through intragastric route for 14 days. Control group were treated with saline, enzyme inducer group were treated with 3.0 mg/kg phenobarbital, enzyme inhibitor group were treated with 40 mg/kg cimetidine and Glycyrrhiza uralensis decoction group were treated with 1.0 g/kg decoction, respectively. Phenacetin, which used as a probe drug, was given to all rats by intra-peritoneal injection on the 15th day. The blood samples were collected at different time points. A developed HPLC method was introduced to determine the concentration of the probe drug in rat plasma and Das software was used to estimate the pharmacokinetic parameters.RESULTS: The t_1/2 value of probe drug in groups of control, enzyme inducer, enzyme inhibitor and Glycyrrhiza uralensis decoction were (104±10),(178±15),(86±9) and(90±9) min, respectively.CONCLUSION: Glycyrrhiza uralensis decoction has inductive effects on rat liver CYP450.

Key words: Glycyrrhiza uralensis decoction, Cytochrome P450, HPLC, Phenacetin