Bitters are a type of alcoholic preparation that is traditionally flavored with botanical matter to create a bitter or bittersweet flavor. They are made by infusing neutral alcohol with herbs, spices, fruits, roots, tree bark, and other botanicals. The botanical ingredients used in preparing bitters have consisted of aromatic herbs, bark, roots, and/or fruit for their flavor and medicinal properties. Some of the more common ingredients are cascarilla, cassia (Chinese cinnamon), gentian, orange peel, and cinchona bark. Most bitters contain both water and alcohol, the latter of which functions as a solvent for botanical extracts as well as a preservative. The alcoholic strength of bitters varies widely across brands and styles. Some modern bitters are made with vegetable glycerin instead, allowing those avoiding alcohol to enjoy them.

Bitters are used to enhance the flavor of cocktails and are an essential ingredient in many staple bar drinks. They are more concentrated than digestive bitters and have extraordinarily strong flavors. Subsequently, bartenders add cocktail bitters in small amounts to their drink recipes and never serve them to customers straight. Bitters can also be used in non-alcoholic drinks, but it depends on the person and how comfortable they are with a very small amount of alcohol. Some of the most commonly used bitters include Angostura bitters, Peychaud’s bitters, and orange bitters.