A fountain drink is a soft drink, prepared locally from a supply of flavored sweetened syrup, carbon dioxide, and water, either manually, in a device called a soda fountain, or in a vending machine which is essentially an automated soda fountain that is operated using a soda gun. Today, the syrup often is pumped from a special container called a Bag-In-Box (BIB).

Also referred to as a post mix machine in some markets.