Oxidative stress rise either as a result of increased free radical production or reduced of antioxidant defense. The levels of LPO, GSH, and several antioxidant enzymes activities were determined in liver, kidney, intestine, spleen, pancrease and adrenal glands of female rats injected with different doses of STZ.It is evident from the study that the immediate pathological effects of STZ are primarily through LPO which was higher with the high dose of STZ. Moreover, STZ released free radicals not only damage B-cells of pancreas by damage other vital organs also.