The anti‐inflammatory activity of cirsilineol in in vivo condition was assessed by measuring the relative organ weight, lung dry/wet weight ratio, protein concentration, and infiltration of inflammatory cells in bronchoalveolar lavage fluid. We estimated the myeloperoxidase activity and levels of cytokines, chemokines, and inflammatory markers to analyze the efficacy of cirsilineol against lipopolysaccharide (LPS)‐induced lung inflammation. Furthermore, we quantified the gene expression of NFkB/IKK signaling molecules in cirsilineol‐treated and untreated acute lung injury mice to confirm the anti‐inflammatory property of cirsilineol. The lung histology was assessed with hematoxylin and eosin staining. Apart from in vivo experiments, in vitro tests with LPS‐stimulated RAW 264.7 macrophages were also performed. Cell viability assay was performed in the presence and absence of LPS in RAW 264.7 macrophages to determine the cytotoxic effect of cirsilineol against macrophages. Reverse‐transcription polymerase chain reaction (RT‐PCR) analysis was done to analyze the gene expression of inflammatory markers in LPS‐treated RAW 264.7 macrophages to prove that cirsilineol effectively inhibits inflammation in vitro. The results of our study prove that cirsilineol effectively inhibits inflammation in both in vivo and in vitro conditions. RT‐PCR analysis results of NFkB/IKK signaling molecules clearly illustrate that cirsilineol inhibited the expression of NFkB/IKK signaling protein and thereby prevented inflammation in in vivo condition, and it is further confirmed with the results of inflammatory protein expression in vitro model. The lung histopathological studies authentically confirm that cirsilineol potentially prevented the mice from LPS‐induced lung inflammation.