The present invention discloses methods of making a mixture of theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate and theaflavin 3,3'-digallate, pharmaceutical compositions of the above mixture of theaflavins, diet supplement compositions of the above mixture of theaflavins and methods for using the above mixtures of theaflavin and pharmaceutical compositions thereof to treat or prevent various diseases. The present invention also discloses methods of making theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate and theaflavin 3,3'-digallate, each as a separate compound, pharmaceutical compositions of the above compounds, diet supplement compositions of the above compounds and methods for using the above compounds to treat or prevent various diseases.