Silybin is one of the main flavonoids produced by milk thistle, which has been used in the treatment of liver diseases. In this study, we examined the protective effects and possible mechanisms of action of silybin in lipopolysaccharide (LPS)‑induced lung injury and inflammation. Pre-treatment of mice with silybin significantly inhibited LPS-induced airway inflammatory cell recruitment, including macrophages, T cells and neutrophils. The production of cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in bronchoalveolar fluid and serum was also decreased following treatment with silybin. Elevated cytokine mRNA levels induced by LPS in lung tissue were all suppressed by silybin and lung histological alterations were also improved. In addition, experiments using cells indicated that silybin significantly decreased the mRNA levels and secretion of IL-1β and TNF-α in THP-1 cells. Moreover, the mechanisms responsible for these effects were attributed to the inhibitory effect of silybin on nuclear factor-κB (NF-κB) signaling and NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. The data form our study thus support the utility of silybin as a potential medicine for the treatment of acute lung injury‑associated inflammation and pathological changes. Silybin exerts protective effects against lung injury by regulating NF-κB signaling and the NLRP3 inflammasome activation.