This chapter provides details about the production, trade, and consumption of caffeine, which is probably the world's most widely used drug. The focus is on caffeine derived from coffee, which accounts for about 54% of all caffeine use, because other chapters in the volume give details of tea and cocoa consumption. Tea accounts for about 43% of all caffeine consumption. Total world caffeine consumption in 1981 was estimated to be approximately 120,000 tonnes, equivalent to 70 mg a day for each inhabitant. The per capita rate of caffeine use in Canada and the United States is approximately three times that for the world as a whole, but only half that of a heavy coffee-consuming country such as Sweden or a heavy tea-consuming country such as the United Kingdom.