Green tea is one of the main tea leaves in China, which refers to a beverage made from the new leaves or buds of tea trees without fermentation, and through the processes of enzyme fixation, shaping and drying. The color of the finished product and the brewed tea soup retain the green style of new tea. Without fermentation, green tea retains the natural substances of fresh leaves, and contains many nutrients such as tea polyphenols, catechins, chlorophyll, caffeine, amino acids and vitamins. These natural nutrients in green tea have special effects of anti-aging, anti-cancer, sterilization and anti-inflammation, which are beyond the reach of other teas. Green tea is a kind of tea made from suitable new shoots of tea trees through typical technological processes such as enzyme fixation, rolling and drying. Its dry tea color and brewed tea soup and tea leaves are mainly green, hence the name green tea. Green tea is made from fresh leaves picked by high temperature to kill various oxidases, keep the tea green, and then knead and dry. Clear soup and green leaves are the same characteristics of green tea quality. China produces all kinds of green tea. Henan, Guizhou, Jiangxi, Anhui, Zhejiang, Jiangsu, Sichuan, Shaanxi (southern Shaanxi), Hunan, Hubei, Guangxi and Fujian are the main green tea producing provinces in China.

Green tea is not as fresh as possible. If the storage time of green tea is too short, the contents of tea polyphenols and some volatile components are relatively high, which has a strong stimulating effect on human gastrointestinal mucosa. Gastrointestinal function is weak, especially in patients with chronic gastritis and ulcer. After drinking new tea, they may have symptoms such as headache, palpitation, epigastric discomfort and even slight dizziness.

In addition, fresh tea contains more caffeine and theophylline, and people with autonomic nerve dysfunction and high cerebral cortex excitability may have symptoms such as insomnia, fatigue, sweating and frequent urination after drinking. Therefore, people with weak gastrointestinal function, autonomic nerve dysfunction and high cerebral cortex excitability can put new tea for a month or two before drinking, put less tea and don't drink too much.