People have drunk caffeine for thousands of years. For early man it was usually in teas and herbs that they consumed. Early records give evidence that Emperor Shen Nung of China drank a strong black tea in around 2700 BCE. However it wasn't until 575 AD that the most popular beverage containing Caffeine came about. It was in 575 in Africa that Coffee beans were used for consumption and currency. In South America there is proof that the the Aztecs drank coffee. In America there was a switch from coffee to tea in the eighteenth century due to the taxes put on tea by the British. In 1958 the FDA recognized Caffeine as a generally safe substance (Caffeine|LIVESTRONG).