In an attempt for utilization of some common spices, cinnamon bark, clove bud and ginger rhi-zom are popular implementations because of their flavoring and antioxidative activity, which mainly comes from polyphenols. The aim of the study was to investigate the effect of spices or their essential oils compared with Diamicron30MR (60mg /100g diet) on the occurrence of oxidative stress in serum of induced diabetic rats by measuring the extent of oxidative damage as well as the status of the anti-oxidant defense system. Albino rats weighing 150 ± 5 g were injected with STZ (50 mg/kg) intraperi-toneally for induction of diabetes mellitus. Rats were divided into 17groups (each of 8 rats) of non-diabetic ,diabetic non-treated and diabetic treated rats with spice powders or their essential oils and mixtures. After 8 weeks, the diabetic rats fed on spices or their essential oils significantly decreased levels of blood glucose and significantly increased insulin level. The treatment also resulted in a sig-nificant improvement in lipid profile, liver functions and kidney functions. However, a significantly in-crement in the activities of glutathione peroxidase (GPH-Px) and concentration of glutathione (GSH) were observed in blood of diabetic rats treated with all of the essential oils. The treated groups showed a significant decrement in thiobarbituric acid reac-tive substances (TBARS) in serum. Since the study of induction of the redox enzymes is considered to be a reliable marker for evaluating the antiperoxi-dative efficacy of the spices, these findings sug-gest a possible antiperoxidative role derived from such essential oils. Treatment with spices or their essential oils reduces the hepatic, renal, pancreat-ic and cardiac histopathological abnormalities as-sociated with STZ – induced diabetes mellitus