the cannabis plant has a history of medicinal use dating back thousands of years across many cultures. the yanghai tombs, a vast ancient cemetery situated in the turfan district of the xinjiang uyghur autonomous region of the people’s republic of china, have revealed the 2700-year-old grave of a shaman. near the head and foot of the shaman was a large leather basket and wooden bowl filled with 789g of cannabis, superbly preserved by climatic and burial conditions. an international team demonstrated that this material contained tetrahydrocannabinol (thc), the psychoactive component of cannabis, casting doubt on the theory that ancients only grew the plant for hemp in order to make clothing, rope and other objects. the cannabis was presumably employed by this culture as a medicinal or psychoactive agent, or an aid to divination. this is the oldest documentation of cannabis as a pharmacologically active agent.