Used for thousands of years in China, kombucha has recently become popular in the United States. Kombucha is essentially a fermented mixture made from the kombucha culture and yeast added to a black or green tea with sugar. The end result is a kind of sweet, pancake-like structure that floats to the top of the bottle where it is stored. The fermentation is often referred to as a "mushroom." The tea is said to be a miracle cure, but most of these claims have not been established within the medical community.
Kombucha is known for its detoxification abilities. The tea has been said to help the elderly and HIV patients and even to assist in curing hangovers. Because of its acidic properties, the tea has been found to kill bacteria in the body.
Beyond detoxing, the drink is thought to help stir the immune system, increase energy, stimulate hair growth and prevent cancer. According to a New York Times article, the popular and trendy drink has also been said to restore hair color, help arthritis patients and improve skin, but again, many of these claims remain unfounded and untested in peer-reviewed experiments involving humans.
The effectiveness of kombucha has been frequently called into question. While some say it can help fight off certain disorders and aid digestion, other studies have found that the tea can actually be detrimental. According to a Centers for Disease Control (CDC) memo, Kombucha consumption was linked to a death in the mid-1990s when acid built up in the body of an Iowa woman, causing metabolic acidosis. A few other cases of kombucha causing illness, rather than allaying it, have been reported as well, but many of those cases are linked to home-brewing the drink.
According to an article in the Los Angeles Times, studies on lab mice that were given the drink for three years found that the mice lived nearly a month longer than the mice in a test group not given the drink. The Los Angeles Times article also cited studies showing the positive effects on the mice's livers and DNA even after exposure to outside negative influences. Unfortunately, no clinical trials have been conducted on humans, so it's unclear what kind of effects the drink has on people.
In short, it is difficult to tell how effective kombucha is as a drink. Until some solid, peer-reviewed test results are published on its use, it is only possible to speculate on the drink's benefits and whether its benefits outweigh its potential dangers. To lessen the gap between the benefits and dangers, always maintain clean conditions and follow regulations when home-brewing the drink, or stick to mass-produced bottles.