A bitters is an alcoholic beverage that contains herbal essences and citrus flavouring and has a bitter or bittersweet flavour.There are numerous brands of bitters, which were formerly marketed as patent medicines but are now considered to be digestifs rather than medicines.
Bitters are principally used as digestifs and as flavorings in cocktails While bitters commonly have an alcoholic strength of up to 45%, they are normally consumed in small amounts, added as a flavouring agent (similar to vanilla flavouring, which is also dissolved in alcohol.) In the United Kingdom Angostura Bitters are not classified as alcoholic beverages due to their bitter taste and can be bought by a person of any age.