Green tea has many functions, such as refreshing brain, relieving fever and thirst, promoting digestion and relieving annoyance, sterilizing and diminishing inflammation, preventing caries and strengthening teeth, reducing weight and building body, regulating stomach and diuresis, improving eyesight and clearing heart, quitting smoking and sobering up, lowering blood pressure and reducing fat, resisting cancer, increasing the elasticity of blood vessel wall and preventing atomic radiation damage. However, it is not advisable to drink too much or too much, so as to be moderate and timely, and it is best not to drink for people with gastrointestinal discomfort.