"Here, have a coke! It's refreshing!"
Today, the coca and cola extracts have been removed, and artificial flavorings are used instead. Other ingredients are sugar (corn syrup are used in some parts of the world), caramel coloring, water and phosphoric or citric acid.
The Coca-Cola is used as a mixer in the bar, and several famous recipes use it as a main ingredient. Without it, drinks like the Long Island Iced Tea and Rum and Coke would not exist.