Some of the various medical conditions that may be helpful to treat or combat are cancer, rheumatoid arthritis, high cholesterol levels, cardiovascular disease, infection, and impaired immune function. Green tea has been proven to be so effective beacause it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant that helps to kill cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.
So maybe it would not be such a bad idea to start drinking green tea, or even supplementing with it especially if you have a predisposition to develop any of the disorders in which it treats. Not to mention, it tastes pretty good as well. You must consider, though, that green tea generally contains caffeine and should not be taken before bed or if you are sensitive to caffeine.