What are the benefits of drinking black tea to health?

There are many resources that indicate a herb for100 different uses but the truth is I don't really believe these resources. What I am sure of by basic scientific reason and at the top of my mind is that Tea contains astringent properties due to its content of catechins which may help with diarrhoea and it contains caffeine in a complex form which means that it is slower in releasing it therefore acts as a stimlant over a longer period of time than other caffeine containing stimulants (eg. coffee)