What the heck is Kombucha? And what is in Kombucha? Kombucha also known as BOOCH is a fermented tea beverage that originated in China around 220 B.C. The name is supposedly derived from a Korean doctor that brought the fermented tea to Japan as a cure for an Emperor, the doctors name is Dr. Kombu. It has been told there are many legends of this but many point to Dr. Kombu.