When tea is used as a beverage in daily life, it does not have any efficacy and effect of medicine. But tea is rich in nutrients, can help the human body to supplement the required nutrients such as tea polyphenols, has a certain nutritional value, common tea green tea, black tea, white tea and so on. 1. Green tea: green tea is unfermented tea, green tea contains fluorine, tea polyphenols, vitamins and other ingredients, including vitamin A, vitamin E content, and contains a variety of trace elements, such as phosphorus, calcium, potassium, sodium, magnesium, sulfur and so on. 2. Black tea: black tea is a kind of tea made of full fermentation, black tea is rich in carotene, phosphorus, magnesium, potassium, caffeine, theaflavin, theaflavin and other nutrients. 3. White tea: white tea is a micro-fermented tea, white tea contains a large number of amino acids, vitamins and other substances, such as tea polyphenols, tea polysaccharides, theanine, caffeine, antioxidant vitamins, γ-amino butyric acid, tea saponins and so on. Appropriate consumption of tea can help the body to supplement the required nutrients, is good for health, but tea as a beverage when, can not play any drug efficacy and function, can not achieve the purpose of treatment of disease. Tea caffeine and other components can excite the central nervous system, insomnia after drinking the crowd will aggravate insomnia, so insomnia people should not drink tea. Tea can stimulate the gastroesophageal sphincter, gastric ulcer, gastroesophageal reflux and other people should not drink strong tea to avoid aggravating stomach discomfort. Drinking tea needs to be in moderation, avoid overdrinking, so as not to cause adverse reactions.