Bitters are alcoholic liquids flavored with herbs, spices, fruits and barks to impart bitterness. They developed in the 1800s as supposed cure-alls but are now used primarily in cocktails. There are two main types - those used for flavoring like Angostura and Underberg, and bitter liqueurs taken as appetizers like Campari, Cynar and Lillet. Popular bitter liqueurs are made from wine or spirits and herbs and have distinct flavors from dry to syrupy. Bitters are featured ingredients in classic cocktails like the Negroni, Americano and Pink Gin.