The main chemical compunds with benefits for health in green tea are caffeine and theanine. Caffeine being a phosphodiesterase inhibitor brings about most of the effects related to weight reduction and lowering cholesterol. Theanine boosts up the cognitive effects for a short period of time providing you with relaxation as well as alertness at the same time.
In addition, green tea prevents the intake of other beverages such as coffee, which have beneficial as well as some harmful effects (e.g. - inducing gastritis, chronic pancreatitis, pancreatic carcinoma)
Therefore, intake of green tea is beneficial for your health.