::::::, edit warring requires at least two editors and by repeatedly inserting your text while reverting, you are in fact edit-warring along with the other editors.  

 ::::::You've said that extraordinary claims require extraordinary evidence. I take it that you mean that saying someone died because of ingesting kombucha is an extraordinary claim and that somehow the reference that supports that people died isn't extraordinary enough. Death due to the ingestion of a substance isn't an extraordinary circumstance at all; it would be much more remarkable if no one died after ingesting a particular something.  

 ::::::To comply with MEDRS means to use the best available sources - that's what the guideline boils down to. When something like kombucha isn't well-researched, we have to use the best sources out there. These sources may not appear on PUBMED; they may be older than five years; they may even be case studies. The fact that these case reports are themselves reported in review references means that those review references do adhere to MEDRS. That's the way reviews work - they review the available literature and that can include case reports. 

 :::::: I agree that detailed mention of the adverse effects (including death) doesnt belong in the lead, which is why my lead proposal just says adverse effects have been reported anecdotally. 

 ::::::Since you both appear to be fine with my proposed text I'm going to add it within the next couple of hours, after dinner.