Studies have shown that drinking four cups of green tea a day can reduce the risk of developing stomach and lung cancer as well as heart disease. Green tea contains, among others, the cancer-fighting flavonoid epigallocatechin gallate (ECGC). ECGC is unique in that it seems to battle cancer at all stages. ECGC is as much as 100 times more powerful an antioxidant as vitamin C, and 25 times more powerful than vitamin E. ECGC also may account for the antibacterial properties of green tea.