The　pregnane　X　receptor　(PXR),　a　liver　and　intestine　specific　receptor　has　been　reported　to　be　related　with　the　repression　of　inflammation　as　well　as　activation　of　cytochronnosome　P450　3A　(CYP3A)　expression.　We　examined　the　effect　of　PXR　on　tetrachloromethane　(CCl4)-induced　mouse　liver　inflammation　in　this　work.　Ginkgolide　A,　one　main　component　of　Ginkgo　biloba　extracts　(GBE),　activated　PXR　and　enhanced　PXR　expression　level,　displayed　both　significant　therapeutic　effect　and　preventive　effect　against　CCl4-induced　mouse　hepatitis.　siRNA-mediated　decrease　of　PXR　expression　significantly　reduced　the　efficacy　of　Ginkgolide　A　in　treating　CCl4-induced　inflammation　in　mice.　Flavonoids,　another　important　components　of　GBE,　were　shown　anti-inflammatory　effect　in　a　different　way　from　Ginkgolide　A　which　might　be　independent　on　PXR　because　flavonoids　significantly　inhibited　CYP3A11　activities　in　mice.　The　results　indicated　that　anti-inflammatory　effect　of　PXR　might　be　mediated　by　enhancing　transcription　level　of　I　kappa　B　alpha　through　binding　of　I　kappa　B　alpha.　Inhibition　of　NF-kappa　B　activity　by　NF-kappa　B-specific　suppressor　I　kappa　B　alpha　is　one　of　the　potential　mechanisms　of　Ginkgolide　A　against　CCl4-induced　liver　inflammation.