Caffeine is the world's favorite psychoactive substance.
Only petroleum exceeds coffee as a globally traded commodity, and US commerce and history are closely linked to tea consumption. Soft drinks now rank as the most popular beverage in the US, and most are caffeinated. Beverage trade groups estimate the annual per capita soft drink consumption rate at 56 gallons. Research and worldwide beverage experience confirm the safety of moderate caffeine consumption in healthy individuals. The universal appeal of caffeine is related to its psycho-stimulant properties.