After water, tea is the beverage that people drink the most worldwide. Caffeine, amino acids, and polyphenols are the main chemical constituents of green tea. (-)-epigallocatechin-3-gallate is the most prevalent catechin in green tea, which is rich in them. The natural phenol and antioxidant known as catechin are assumed to be the cause of many of the health advantages of green tea. It has been discovered that diets supplemented with many of these components of green tea, but especially with the diet combining caffeine and catechin, significantly reduced weight growth. According to recent human research, green tea may help lower the risk of cardiovascular disease and support other physiological processes like body weight control, an antioxidant-like impact, an anti-hypertensive effect, an effect on obesity, the effect of green tea on diabetes, and an effect on the liver. Green tea has been added to the list of beverages having functional qualities due to growing interest in its health benefits. The advantages and disadvantages of drinking tea are still up for debate, but the innumerable health benefits of tea much outweigh the few known harmful consequences.

Keywords: Green tea, green tea polyphenols, theophylline, caffeine, (-)-epigallocatechin-3-gallate (EGCG), antioxidant, obesity, blood pressure, liver. Diabetes.