|1. Caffeine and caffeinelike alkaloids have a stimulating effect on the central nervous system.
2. Coffea arabica, Thea sinensis, and Theobroma cacao, plants naturally rich in caffeine, have long been used as sources of stimulating beverages and historically have played an important role in human affairs.
3. Today coffee, tea, chocolate, and cola are consumed globally and are a mixed blessing to the world’s population.