In the present study, we analyzed the role of Ginkgo biloba extract in lipopolysaccharide(LPS)-induced acute lung injury(ALI). ALI was induced in mice by intratracheal instillation of LPS. G. biloba extract(12 and 24 mg·kg-1) and dexamethasone(2 mg·kg-1), as a positive control, were given by i.p. injection. The cells in the bronchoalveolar lavage fluid(BALF) were counted. The degree of animal lung edema was evaluated by measuring the wet/dry weight ratio. The superoxidase dismutase(SOD) and myeloperoxidase(MPO) activities were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators, tumor necrosis factor-α, interleukin-1β, and interleukin-6, were assayed by enzyme-linked immunosorbent assay. Pathological changes of lung tissues were observed by H&E staining. The levels of NF-κB p65 and COX-2 expression were detected by Western blotting. Compared to the LPS group, the treatment with the G. biloba extract at 12 and 24 mg·kg-1 markedly attenuated the inflammatory cell numbers in the BALF, decreased NF-κB p65 and COX-2 expression, and improved SOD activity, and inhibited MPO activity. The histological changes of the lungs were also significantly improved. The results indicated that G. biloba extract has a protective effect on LPS-induced acute lung injury in mice. The protective mechanism of G. biloba extract may be partly attributed to the inhibition of NF-κB p65 and COX-2 activation. In the present study, we analyzed the role of Ginkgo biloba extract in lipopolysaccharide (LPS) -induced acute lung injury (ALI). ALI was induced in mice by intratracheal instillation of LPS. G. biloba extract (12 and 24 mg · kg- 1) and dexamethasone (2 mg · kg -1), as a positive control, were given by ip injection. The degree of animal lung edema was evaluated by measuring the wet / dry weight ratio. The superoxidase dismutase (SOD) and myeloperoxidase (MPO) activities were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators, tumor necrosis factor-α, interleukin-1β, and interleukin-6, were assayed by Compared to lung tissues were observed by H & E staining. The levels of NF-κB p65 and COX-2 expression were detected by Western blotting. Compared to the LPS group, the treatment with the G. biloba extract at 12 and 24 mg · kg-1 markedly attenuated the inflamma The histological changes of the lungs were also significantly improved. The results indicated that G. biloba extract has a protective effect on the BALF, decreased NF-κB p65 and COX-2 expression, and improved SOD activity, and inhibited MPO activity. effect on LPS-induced acute lung injury in mice. The protective mechanism of G. biloba extract may be partly attributed to the inhibition of NF-κB p65 and COX-2 activation.