Background and Objective: Nitrite is widely used in food, pharmaceutical and chemical products. This study was performed to examine the effects of sodium nitrite on liver histopathology and enzyme and nitric oxide in adult Wistar male rats.

Materials and Methods: In this experimental study, 30 adult male Wistar rats were randomly divided into three experimental groups of 10, consisting of one control group and two experimental groups (one group receiving 100 mg/kg/day and the other 300 mg/kg/day of sodium nitrite in drinking water for 60 days). Blood samples were collected to determine serum levels of AST, ALT, ALP and nitric oxide. After sacrifying the rats, the rat’s liver tissues were removed for histopathological evaluation (using Hematoxylin-Eosin staining). The obtained results were analyzed statistically.

Results: Use of sodium nitrite in both experimental groups caused a significant increase in serum AST, ALT, ALP and nitric oxide compared to the control group) p ≥0.0 (. In the group receiving 300 mg/kg/day of sodium nitrite, dilatation and congestion of hepatic sinusoids with infiltration of mononuclear inflammatory cells in addition to sinusoid cell proliferation was observed.

Conclusion: Sodium nitrite increases nitric oxide levels and damages hepatocytes, therefore it is a risk factor for liver disease and should be replaced with a suitable and healthy substance in the food industry.