In America "Kombucha" is popular among the people who are interested in health the past few years. It is same as "Kocha-kinoko" which was boomed in Japan about 40 years ago. It's not Japanese tea from kelp (kombu) powder.
Kombucha is the fermenting black or green tea using acetic acid bacteria, lactic acid bacteria and yeast. It is said that helps detox of liver, lowers blood cholesterol, helps the function of intestine and clears the skin. But they are not supported by scientific evidence so far.
I got the base of drink from my friend and made it at home. The flavor is like apple vinegar so I drink it adding ices or water.