From the Manufacturer:
Nature's Way green tea is now a low caffeine technically advanced herbal extract standardized to 90% polyphenols with a guaranteed level of 55% epigallocatechin gallate. Population studies in Japan have proven the remarkable health benefits derived from regular consumption of green tea. These benefits are due to the presence of polyphenols such as epigallocatechin gallate--the primary substance responsible for green tea's powerful antioxidant protection in the body.