The protective effect of green tea (Camellia sinensis) was tested against arsenic-induced toxicity. However, the possible role of tannins in green tea in alleviating hepatic and renal oxidative injury has also been studied. Administration of sodium arsenite (100 mg/kg/day) for 28 days in Sprague Dawley female rats resulted in significant reduction of biochemical parameters such as delta-aminolevulinic acid dehydratase (ALAD), reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and elevation of thiobarbituric acid reactive substances (TBARS) and the index of nitrite/nitrate (NOx) levels. The tissue arsenic burden was increased after arsenic exposure for a period of 28 days. Green tea crude fraction (GTC) co-treated with sodium arsenite for 28 days caused significant (p < .01) elevation of ALAD, GSH, GPx, SOD, and nitrate/nitrite levels and reduction of the TBARS level and tissue burden when compared to detannified green tea fraction (GTDT)-treated groups. The protective role of tannin-rich fraction of C. sinensis when compared to the detannified fraction was also confirmed by histological examinations. The greater activity of GTC than that of detannified green tea fraction correlates with the higher content of tannins in green tea. Overall, these results indicate that the tannin-rich green tea could have improved the defense mechanism against arsenic-induced oxidative stress and reduced the tissue arsenic burden.