The use of herbal and dietary supplements (HDSs) is widespread and growing due to the popular notion that these products are of natural origins and safe. Kombucha (or \"mushroom\") tea is one HDS that is consumed by people for various perceived health benefits. Kombucha tea is a well-known health beverage made by fermenting sweet black tea with a round, flat, gray fungus for a week or longer. There is concern, however, from the evidence of a few case reports currently available, that it may pose life-threatening and/or adverse effects for users.