Aim: The purpose of the study is to research the effect of quercetin, which has a good antioxidant characteristic in rats exposed to sodium fluoride (NaF) toxication, on oxidant and antioxidant activity in liver tissue and erythrocyte. Material and method: 40 Swiss albino male rats with a weight of approximately 20–25 gr were used in the study. The rats were separated into 4 equal groups (n = 10). The first group, the control group, was given normal drinking water; the second group was given 12 mg/kg/day NaF; the third group was given 40 mg/kg/day quercetin; the fourth group was given 12 mg/kg/day NaF+40 mg/kg/day quercetin orally for 30 days. As a result of the experiment, plasma AST and ALT activities were found. Total oxidant capacity (TOC) and total antioxidant capacity (TAC) analyses were made in liver tissue and erythrocyte hemogenisate. Histopathological analyses of the liver tissue were conducted. Results: No changes were found in plasma ALT activities between groups. Increases were found in AST activity of all groups. While erythrocyte TAC level was found to increase in fluorine and fluorine + quercetin group when compared with the control group, erythrocyte TOC level was found to increase in all groups when compared with the control group. No significant change was found in TOC and TAC levels in the liver tissue. In liver tissue histopathology, while hydropic degeneration and cellular necrosis were found in vena centralis area in fluorine group, hydropic degeneration was found in heptocytes in centrilobular area in the quercetin group. In the fourth group, hydropic degeneration and centrilobular necrosis were more severe. It was found that in rats which are given NaF experimentally, fluorine and quercetin caused histopathological degenerations in the liver tissue during this time. Conclusion: While no changes were found in TOC and TAC levels of liver tissue, antioxidant capacity was found to be stimulated in fluorine groups in erythrocyte.