Tartrazine is routinely used in food and pharmaceutical industries as an azo dye, that imparts yellow color to the products of different food items. Various medicinal plants and herbs are used as protective agents against natural or man-made toxicants. In this study, the protective effect of aqueous onion extract against tartrazine instigated reproductive toxicity in both male and female mice was evaluated. A total of 80 healthy male and female mice (weighing 14 ± 1g) were divided into four groups (n=20).  Group I was marked as control, group II was exposed to tartrazine (10µg/g B.W), group III was exposed to aforementioned concentration of tartrazine and 0.1ml onion extract, while group IV received only 0.1ml onion extract. Mice were treated orally for 30 consecutive days and then euthanized for sample collection. Our findings showed that the total antioxidant capacity of testes and ovaries homogenates reduced significantly after exposure to tartrazine, while co-administration of onion extract and tartrazine improved the anti-oxidant power to a great extent. Hormonal analysis showed that male mice exposed to tartrazine had significantly reduced serum testosterone level while level of estradiol, luteinizing and follicle stimulating hormone was also significantly lower in female mice after exposure of tartrazine. Histopathological lesions were also prevalent in tartrazine exposed testes and ovaries sections as compared to controls. Moreover, exposure to tartrazine resulted in increased number of abnormal sperms and decreased total sperm count in male mice. Overall, it is concluded that onion extract was proved to be a remedial agent against tartrazine induced organ pathologies and biochemical alterations.