Abstract: OBJECTIVE To investigate the effect of isodon ternifolia-containing serum(ITS) on the activation of rat primary hepatic Kupffer cell(KC) induced by lipopolysaccharide(LPS) through TLR4/NF-κB/NLRP3 signal pathway. METHODS The primary KC of rats were isolated and cultured, and the primary KC induced by LPS were divided into blank control group, model control group, blank serum group, positive control group(colchicine containing serum group), ITS group, TLR4 blocker group and TLR4 blocker+ITS group. MTT assay was used to detect the effect of different concentrations of ITS on the proliferation activity of KC. The content of interleukin-1β(IL-1β), interleukin-18(IL-18), tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) in KC supernatant were detected by ELISA. Fluorescence quantitative polymerase chain reaction(PCR), Western blotting and immunofluorescence were used to detect the expression of TLR4, nuclear factor κB inhibitor protein α(IκBα), cysteine protease-1(Caspase-1), NLRP3 mRNA and TLR4, IκBα, phosphorylated IκBα(p-IκBα), Caspase-1, NLRP3 and NF-κBp65 in KC. RESULTS Compared with the model control group, the contents of IL-1β, IL-18, TNF-α and IL-6 in the supernatant of KC and the expression of TLR4, IκB α, Caspase-1, NLRP3 mRNA and TLR4, IκBα, p-IκBα, Caspase-1, NLRP3, NF-κBp65 protein in the supernatant of KC in all drug groups were down-regulated or decreased(P<0.05 or P<0.01). Compared with TLR4 blocker group, the improvement of most of the above indexes in TLR4 blocker+ITS group was more obvious. CONCLUSION Isodon ternifolia may inhibit the activation of KC and reduce the expression and release of inflammatory factors by down-regulating TLR4/NF-κB/NLRP3 signal pathway, thus alleviating the inflammatory injury of liver.