Comment by Cass

Oh, certainly, there's nothing to prove it was the green tea. We did rule out any other cause of liver failure we possibly could, but there's nothing to say we didn't miss something. But green tea in high doses IS a known cause of liver failure (admittedly, not known to us at the time, but there's case studies on pubmed I found once I started searching), so it remained the most likely cause after eliminating anything else plausible apart from the good old doctor standby of "sometimes shit just happens, shrug emoji" also known as "idiopathic."