Atractylenolide I (AO-I), one of the major bioactive components isolated from Rhizoma Atractylodes macrocephala, has been reported to have anti-inflammatory effects. In the present study, we investigated the protective effects of AO-I on acute lung injury (ALI) using LPS-induced ALI mouse model. Lung injury was assessed by histological study. Inflammatory cytokines TNF-alpha, IL-6 and IL-1 beta production were detected by ELISA. TLR4 expression and NF-kappa B activation were measured by western blot analysis. The results showed that treatment of AO-I significantly attenuated LPS-induced lung wet-to-dry weight ratio and MPO activity. Meanwhile, treatment of AO-I significantly inhibited the production of TNF-alpha, IL-6, IL-1 1 beta, IL-13, and MIF production in bronchoalveolar lavage fluid (BALF), as well as neutrophils and macrophages in BALE. AO-1 could up-regulate the production of IL-10 in BALF. Besides, LPS-induced TLR4 expression and NF-kappa B activation were suppressed by treatment of AO-I. In conclusion, the current study suggested that AO-I protected mice acute lung injury induced by LPS via inhibition of TLR4 expression and NF-kappa B activation. (C) 2015 Elsevier B.V. All rights reserved.