Kombucha is a fizzy sweet-and-sour drink made with tea. Many people say it helps relieve or prevent a variety of health problems.

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The basic ingredients in kombucha are yeast, sugar, and black tea. The mix is set aside for a week or more. During that time, bacteria and acids form in the drink, as well as a small amount of alcohol. This process is known as fermentation, and it’s similar to how cabbage is preserved as sauerkraut or kimchi, or how milk is turned into yogurt.