Human Consumption of Caffeine

Caffeine from natural sources has been consumed and enjoyed by people throughout the world for centuries, dating back to perhaps as early as the Paleolithic period. The widespread natural occurrence of caffeine in a variety of plants undoubtedly played a major role in the long-standing popularity of caffeine-containing products, especially beverages. More than 60 plant species throughout the world have been identified as containing caffeine. Caffeine-containing beverages made form native plants in South America, such as guarana, yoco, and mate, have been traced back to antiquity (Rall 1980). Similarly, North American natives made use of the caffeine-containing cassina.