Caffeine is a naturally occurring compound found in plant species predominantly growing in the Tropic or Sub-Tropic regions of the world. Plants use caffeine as a natural pesticide since it is toxic to insects and other pests.
However, caffeine in small quantities has therapeutic benefits in some mammals. Early human civilizations discovered that consuming plants containing caffeine offered stimulating effects and these plants even were considered sacred in some cases.
Human exploration and trade of tea and coffee soon caused caffeine use to be spread throughout the world and today greater than 80% of the world’s population uses caffeine in some form or another.