Cola drinks are carbonated soft drinks that contain extract of the kola nut. Kola nuts, the seeds of the African kola tree, contain the stimulant caffeine. Coca-Cola, one of the first sodas to contain kola extracts, originally also contained extracts of the coca plant (cocaine). In the early 1900s the cocaine was removed and replaced by additional caffeine.
Drinking cola is part of American and worldwide culture, with many brands competing for a huge and growing consumer market. Colas are now available with sugar or artificial sweeteners, with or without caffeine, and with or without caramel coloring. People seem to like them regardless of the specific ingredients.
see also Caffeine.