The status of nitric oxide oxidation products and antioxidant vitamins were investigated in goats infected with endoparasites and blood parasites (Trichostrongylidae sp. + Protostrongylidae sp. + Eimeria sp. + Babesia sp.), in this study. Eighteen goats were naturally infected with these parasites and ten healthy goats served as controls which had been treated with antiparasitic drugs after parasitological examinations were carried out. The concentrations of nitric oxide oxidation products (nitrate, nitrite) and antioxidant vitamins (vitamins E And C, beta-carotene and retinol) were determined spectrophotometrically in the blood serum of all Pats. The results were expressed as nitrate (mug/ml) 7.25 +/- 1.31-4.69 +/- 0.32; nitrite (mug/ml) 1.52 +/- 0.39-1.64 +/- 0.19; vitamin E (mg/100) 0.13 +/- 0.05-0.42 +/- 0.02; vitamin C (mg/100 ml) 1.49 +/- 0.26-1.46 +/- 0.15; retinol (g/100 ml) 201.51 +/- 15.69-234.081 +/- 45.15; beta-carotene (g/100 ml) 62.71 +/- 7.14-53.95 +/- 3.82. In conclusion, nitrate concentrations of the infected group were higher than controls (p < 0.05) whereas vitamin E levels of the infected group were lower than the control group (p < 0.05). The concentrations of the other indices examined were not statistically different between groups. These results suggest that the parasitic infections have direct effects on the concentrations of vitamin E, an important antioxidant, and on the increase of nitrate levels which may result from the pathophysiological effects of the parasitic infections.