Bitters are divided into digestive bitters and cocktail bitters when it comes to purpose. From its name, digestive bitters are after-dinner drinks formulated to help the drinker digest their meals. On the other hand, the primary purpose of cocktail bitters is to balance out the flavor of cocktails. In their original form, cocktails are mostly only sweet and sour. By adding a dash of bitters into the drink, you can add complexity and depth to the taste, making its flavor profile more complete.