Most teas, such as green, oolong, and black tea come from the leave of the Camellia sinesis plant. The difference between green tea and the rest of the teas is the way it is processed. Green tea is steamed, which prevents the epigallocatechin gallate medicinal compound from being oxidized. Black and oolong tea leaves come from fermented leaves, which washes out the medicinal compounds and making those teas less effective in fighting diseases. According to recent research, drinking tea, especially green tea can not only refresh your energy, but calm your temper too.