The objective of this study was to verify the effect of the organochalcogen 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on some parameters of oxidative stress in the brain of 10-day-old rats. Cerebral cortex was incubated for 1h in the presence or absence of 1, 10 or 30 microM of 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one and thiobarbituric acid reactive substances (TBARS), carbonyl, sulfhydryl, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), nitric oxide (NO) production and the release of the cytosolic enzyme lactate dehydrogenase (LDH) were measured. The organotellurium was not capable to alter TBARS and carbonyl assays. In contrast, the compound at 10 and 30 microM provoked a reduced of protein thiol groups measured by the sulfhydryl assay. Furthermore, the activity of the antioxidant enzyme CAT (10 and 30 microM) and GPx (1, 10 and 30 microM) was reduced by the organochalcogen. On the other hand, the activity of SOD and GST were enhanced respectively by 1, 10 and 30 microM of the compound. Furthermore, NO production was also increased by 30muM of this organochalcogen. Finally, we verified that the organotellurium was capable of enhance the LDH release at 30 microM concentration. Our findings indicate that this organotellurium compound induces in vitro oxidative stress in the cerebral cortex of rats being potentially toxic for the brain of rats.