Are there any adverse side effects of drinking green tea?

Watch caffeine: Green tea is proven to have remarkable health benefits because it's rich in antioxidant polyphenols known as catechins, as well as L-theanine which has a calming effect. In general the more the better but it does have some caffeine and too much caffeine can make you jittery, raise blood pressure etc. so consider decaf if drinking lots. See http://tinyurl.com/nrafp28 and http://tinyurl.com/zrpxkrx