Kombucha (Russian: chaynyy grib (чайный гриб), Chinese: chájūn (茶菌), Korean: hongchabeoseotcha (홍차버섯차), Japanese: kōcha-kinoko (紅茶キノコ)), is a lightly effervescent fermented drink of sweetened black and/or green tea that is used as a functional food. It is produced by fermenting the tea using a symbiotic colony of bacteria and yeast, or “SCOBY”. Although kombucha is claimed to have several beneficial effects on health, the claims are not supported by scientific evidence. Drinking kombucha has been linked, in rare cases, to serious side effects and deaths, and improper preparation can lead to contamination.