Materials and Methods: Forty male Wistar were divided into four groups of 10. The first group was used as the control group and were given only water without additives, group 2 were given tartrazine, group 3 were given tartrazine plus onion juice and the fourth group which was given only onion juice through gastric gavage. The experiment was conducted for 60 days, then the antioxidant activities superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and biochemical parameters namely high density lipoprotein (HDL), low density lipoprotein (LDL) and testosterone together with the histopathological studies (sperm count and testicular weight) were measured.

Results: Tartrazine caused a decrease in the activity of antioxidant enzymes (SOD, CAT, GPX) and a decrease in the level of testosterone and HDL and also a decrease in sperm count and testicular tissue weight. Tartrazine caused an increase in the LDL levels.

Conclusion: Results showed that consumption of tartrazine is associated with production of free radicals and in turn causes significant decrease in antioxidant activities and biochemical serum factors which damage the cellular compartments of the testis. Onion as an antioxidant in this study reduces the damaging effects of tartrazine on the enzymatic activities of antioxidant and biochemical serum factors.