The kombucha phenomenon has all the right elements to brew up a marketing storm: a cool name, exotic pedigree, mystical aura and, of course, purported health benefits. Immune-boosting, cancer prevention, and complexion clearing are just a few of the amazing powers attributed to kombucha, a black, sweetened tea fermented with yeast and bacteria. While proponents will often create their own, homegrown kombucha "mushrooms" (the fermenting, bacterial mass that cultures the tea), the kombucha business is booming as well, with commercial sales skyrocketing 122% over the past three years.

 
Relatively nutrient poor, it's the brew's probiotic bacteria that are promoted as the driving therapeutic agent. But according to the American Cancer Society, "Since cultures and preparation methods vary, Kombucha tea may contain contaminants such as molds and fungi, some of which can cause illness." A search of medical literature reveals three studies suggesting antimicrobial and anti-viral activity among rats. No human studies support any of the purported benefits -- but alarmingly several citations include human case studies of severe illness, particularly among those with already compromised immune systems.

 
Bottom line: Instead of kombucha, opt for regular black tea or green tea, both of which have potential benefits and no known health risks.