Oxidative stress is involved in the pathophysiology of neurodegenerative diseases and aging. Many species of the genus Sideritis (mountain tea) are widely consumed in the Mediterranean region as herbal tea. This study evaluated the effect of supplementation of mice with herbal tea from Sideritis clandestina subsp. peloponnesiaca on the antioxidant status of different brain regions. To select the most bioactive herbal tea, the polyphenolic content (Folin-Ciocalteu method) and the antioxidant properties (ferric reducing antioxidant power [FRAP] and 2,2-diphenyl-1-picrylhydrazyl assays) of several taxa and different populations of the S. clandestina infusions were measured in vitro. Male adult mice had ad libitum access to water (control) or the herbal tea (4% w/v) for 6 weeks. At the end of the treatment period we assessed the total antioxidant power (FRAP assay) and the levels of malondialdehyde (indicator of lipid peroxidation) and reduced glutathione in the cerebral cortex, cerebellum, and midbrain. These biochemical measures have also been determined in liver samples used as a comparative reference peripheral tissue. Consumption of 4% herbal tea increased the total antioxidant power of the midbrain by 72% (P<.05); a significant (P<.05) decrease in malondialdehyde levels and increase in reduced glutathione content of the cerebellum (78% and 27%, respectively) and midbrain (59% and 32%, respectively) were also observed. These findings indicate that mountain tea consumption enhances the antioxidant defense of the adult rodent brain in a region-specific manner.