formatting link
/ well, from an article in Chemical Research in Toxicology, vol 20, p583 ... if anyone has access to that
not very surprising since anything in large quantities is bad
"Problems are likely in people who take supplements, which can contain up to 50 times as much polyphenol as a single cup of tea." ... "liver toxicity" in humans... dont know what the actual findings were - probably just by liver enzyme blood tests, not by biopsy to see if any real damage happened.
But they did manage to kill a couple lab animals with large doses of polyphenols, i guess from liver failure.