Abstract: Objective To study combined effect of sodium nitrite(Na₂NO₂) and sodium sulfite(Na₂SO₃) on function of human liver cell L-02.Methods With 3×3 factorial experimental design, the L-02 cells were exposed to various dosages of Na₂NO₂(low, high), Na₂SO₃(low, high), and Na₂NO₂ plus Na₂SO₃(low Na₂NO₂+low Na₂SO₃, low Na₂NO₂ + high Na₂SO₃, high Na₂NO₂ + low Na₂SO₃, high Na₂NO₂ + high Na₂SO₃) for 24 hours and the L-02 cells without exposure were used as the control.Cell viability was detected with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide(MTT) assay.The concentration of lactate dehydrogenase(LDH), alanine aminotransferase(ALT), aspartate aminotransferase(AST), superoxide dismutase(SOD), glutathione(GSH), and malondialdelyde(MDA) were determined with enzyme-linked immunosorbent assay(ELISA).Results ALT and MDA in L-02 cells increased with the dosages of Na₂NO₂ and Na₂SO₃ in a dose-dependent manner.Significantly higher ALT in L-02 cells of high Na₂NO₂+high Na₂SO₃ group and lower MDA in L-02 cells of high Na₂NO₂+high Na₂SO₃ and high Na₂NO₂+low Na₂SO₃ group were observed compared to those in L-02 cells of single high Na₂NO₂ and single high Na₂SO₃ groups(all P<0.01).Na₂NO₂ and Na₂SO₃ showed obvious interactive effect on ALT and MDA contents(both P<0.05) and no significant interactive effect on contents of LDH, AST, SOD, and GSH(all P>0.05) in L-02 cells.Conclusion Sodium nitrite and sodium sulfite has combined toxic effect on liver cells and the mechanism of the effect maybe be related to the damage of liver cell membrane and oxidative stress;sodium nitrite and sodium sulfite has antagonistic effect on ALT in cell supernatant and antagonistic or synergistic effect on MDA when L-02 cells exposed to the two agents combined.