<p><b>OBJECTIVE</b>To study the influence of selenium and fluoride on apoptosis and lipid peroxidation in humanhepatocytesin vitro.</p><p><b>METHODS</b>The apoptosis, cell cycle, GSH content and lipid peroxides (LPO) level in humanhepatocytes, LPO level and LDH, AST and ALT activity in cell culture supernatants were investigated after hepatocytes were incubated with selenium and/or fluoride for around 12 hours periods in vitro.</p><p><b>RESULTS</b>The percentage of hepatocyteapoptosis bodies (15.557 +/- 2.056)%, the number of cells in S phase (4.823 +/- 0.454)% and LPO level in livertissue and supernatant [(2.884 +/- 0.589) and (3.547 +/- 0.561) nmol/L MDA/mg.prot, respectively], AST and LDH activity in supernatants (91.1 +/- 36.4 and 140.4 +/- 7.6 U/L, respectively) in the fluoride treated group was higher than the control group [(10.313 +/- 1.023)%, (3.253 +/- 0.743)%, (1.473 +/- 0.401) nmol/L MDA/mg.prot, (1.694 +/- 0.443) nmol/L MDA/mg.prot, (54.5 +/- 3.2) U/L and (126.4 +/- 2.6) U/L, respectively], The GSH content in live tissue [(4.225 +/- 0.781) microgram/mg.prot] is lower than control group [(7.595 +/- 1.042) microgram/mg.prot]. Seleniumtreatment reduced these kinds of toxicity of fluoride through raising GSH content, reducing LPO level, LDH and AST activity and percentage of apoptosis bodies.</p><p><b>CONCLUSIONS</b>Selenium can antagonist apoptosis and lipid peroxidation of hepatocytes induced by fluoride.</p>