Green tea has received much attention as protective agent against cardiovascular disease and cancer,the two primary targets of preventive medicine.Since our first demonstration in 1999 of the involvement of endothelium-derived nitric oxide in the acute vasodilator effect of green tea polyphenols,several new vascular protective effects of green tea catechins have been identified.Theaflavins are another class of polyphenol pigments found in black tea,however,little is known about their bioactivity in the vascular system.We have recently demonstrated that black tea and its theaflavins cause relaxations of rat aortas via endothelial nitric oxide-dependent mechanisms and the tea polyphenols are very effective in protecting endothelial function agonist oxidative stress.The present results support the vascular benefit of consumption of black tea,which is equal to that of drinking green tea in terms of their endothelial cell protection and antioxidant capacity. Green tea has received very attention as protective agent against cardiovascular disease and cancer,the two primary targets of preventive medicine.Since our first demonstration in 1999 of the involvement of endothelium-derived nitric oxide in the acute vasodilator effect of green tea polyphenols,several new Vascular protective effects of green tea catechins have been identified.Theaflavins are another class of polyphenol pigments found in black tea,however,little is known about their bioactivity in the vascular system.We have shown that that black tea and its theaflavins cause relaxations of rat Aortas via endothelial nitric oxide-dependent mechanisms and the tea polyphenols are very effective in protecting endothelial function agonist oxidative stress.The present results support the vascular benefit of consumption of black tea,which is equal to that of drinking green tea in terms of their Cell protection and antioxidant capacity.