OBJECTIVE：To isolate and purify baicalin metabolites from rat bile ，and to study its effect on the proliferation of liver cancer HepG 2 cells. METHODS ：Totally of 6 SD rats were collected ，anesthetized and then intubated with bile ducts. They were given baicalin （168 mg/kg）intragastrically after the rats were awake as well as the bile sample 1 was collected during 24 h after intragastric administration. After processed ，bile sample 1 was preliminarily analyzed by HPLC. Another 5 SD rats were anesthetized and intubated in the same way as above ，and then given baicalin intragastrically （400 mg/kg）. The bile sample 2 was collected during 48 h after intragastric administration. After processed ，the bile sample 2 was isolated and purified by semi-preparative HPLC. The isolated metabolites were identified by using UV ，IR，MS and NMR ，as well as based on physical and chemical properties. MTT method combined with high content cell imaging analysis system was used to study the effect of the metabolites on the proliferation of HepG 2 cells. RESULTS ：Baicalin was mainly metabolized into metabolite 1 and metabolite 2 through bile. After isolation and purification ， they were identified as oroxylin A- 7-O-β-D-glucuronide and 2726719792@qq.com baicalein 6-O-β-D-glucuronide. The results of MTT assay showed that the metabolite 2 had a significant inhibitory effect 分析。E-mail：gaoxl@gmc.edu.cn on the proliferation of HepG 2 cells，and its IC 50 was 90 µg/mL；the results of high content cell imaging analysis showed that at a certain concentration metabolite 2 may inhibit proliferation by changing the mitochondrial distribution and membrane permeability of HepG 2 cells（studies on the pharmacological activities of metabolism 1 had been reported ，it was skipped in this study ）. CONCLUSIONS ：In this study ，two baicalin bile metabolites were successfully isolated and identified ，of which baicalein 6-O-β-D-glucuronide has a significant inhibitory effect on the proliferation of HepG 2 cells.