I like green tea, but 20 cups sounds like too much to me. If we are talking about 8 ounce cups, that is over half a gallon of green tea. There is too much caffeine in 20 cups of green tea and even too much water can be harmful at some point. I wonder how much water that woman who drank all that water and did not go to the bathroom to win a Wii, who wound up dying of water intoxication, drank.