Abstract: Objective:To investigate the inhibitory effects and mechanism of allicin on lipopolysaccharide(LPS) -induced inflammatory response in mouse peritoneal macrophages. Methods:A cell model of LPS-induced mouse peritoneal macrophages inflammatory response was established,and which was treated with dexamethasone and different concentrations of allicin. MTT method was used to detect cell viability,and neutral red phagocytosis assay was used to detect phagocytosis ability. Griess assayt was used to detect the NO content,and ELISA assay was used to detect COX-2 enzyme activity and IL-6 secretion. qPCR was used to detected the mRNA expression levels of cyclooxygenase 2(COX-2),nitric oxide synthase(iNOS) and IL-6. Western blot was used to detect the protein expression of COX-2,iNOS and IL-6 and the relative expression of nuclear transcription factor NF-κB p65 and its phosphorylated products. Results:Allicin concentration had no cytotoxic to peritoneal macrophages in the range of 4~160 μg/mL. Compared with the LPS group,the allicin-treated group could promote the phagocytic capacity of peritoneal macrophages,and the inflammatory factors COX-2 enzyme activity and the secretion of NO and IL-6 were significantly inhibited. The genes COX-2,iNOS and IL-6 mRNA and protein relative expression,and phosphorylation of the NF-κB p65 signaling pathway were also significantly inhibited. Conclusion:Allicin could significantly inhibit the LPS-induced inflammatory response of mouse peritoneal macrophages,which would be related with the inhibition of NF-κB signaling pathway.