You may have heard that drinking a steaming beverage when you're hot will make you sweat, and the evaporation of that sweat will then help you cool off. While it's true that the tea will make you damp, it will also increase your body temperature, so you'll need more than a few drops of perspiration to cool you down.
One more thing: Instead of sipping tea, try sticking a green-tea bag under each armpit (the area must be bone-dry first). Pariser says the theory is that the tannic acid may dissolve the outer layer of the skin just enough to create some blockage of the pores. While some of his patients have had success with this home remedy, he says it's still not as effective as antiperspirant.