ABSTRACT

Caffeine is a phytochemical found in a wide variety of plant species distributed throughout the world. Its most common sources are coffee, tea, and cocoa. The incorporation of caffeine into various over-the-counter (OTC) medications implies that it has a useful therapeutic role. Indeed, it is a key constituent in numerous OTC medications for relief from pain and upper respiratory tract conditions, including the common cold and inÀ uenza. Because it is a constituent of a large number of commonly available beverages and foodstuffs ( Table 22.1 ) and its use is generally unregulated and accepted throughout the world, caffeine is believed to be one of the most widely used drugs.