Abstract: OBJECTIVE To investigate the effects of Xuanbai Chengqi (XBCQ) Decoction on lipopolysaccharide-binding protein (LBP) and toll-like receptor 4 (TLR4) mRNA expressions in lipopolysaccharide (LPS) induced acute-lung-injured rat model.METHODS 32 healthy Wistar male rats were randomly divided into 4 groups: normal group， model group， dexamethasone group and XBCQ group. Each group had 8 rats. LPS (6 mg/kg) was injected into the model group and each treatment group to copy ALI animal model. The normal group and model group were given the same volume of physiological saline. The dosage of dexamethasone group was 5mg/kg ip. The dosage of XBCQ group was 7 560 mg/kg ig. The LBP and TLR4 mRNA expressions of lung tissue were measured by real time fluorescence quantitative pcr (RT-PCR). Protein expressions of TLR4 in lung tissue were measured by ismmunohistochemical method. The pathological manifestation of the lung tissue was observed.RESULTS Compared with normal group，the bronchus LBP mRNA of model group and expressions of TLR4 mRNA and staining positive cell area occupation ratio of protein were greatly increased in the model group (P<0.05). Compared with the model group， expressions of TLR4 mRNA and protein were decreased in XBCQ group (P<0.05). Light microscope indicated large areas of pulmonary hemorrhage and necrosis in model group. The pathological changes of XBCQ group were less than the model group. The interstitial inflammation of bronchiole was slight.CONCLUSION XBCQ Decoction can lessen the lung tissue injury of rat caused by endotoxin and has protective effects on lung injury. The mechanism is possibly related to the inhibition of the expressions of TLR4 mRNA and protein in injured lung tissues.