Not just for upset stomachs or sodas, Angostura aromatic bitters are a key ingredient in many cocktails and especially in whiskey cocktails. Though not in the classic recipe, bartenders sometimes add more flavour to the Mojito cocktail by sprinkling a few drops of Angostura bitter on top. Bitters can also be used in soft drinks. Made from a 'secret' formula, developed in 1824 by Dr. Siegert, it is a unique blend of natural herbs and spices which is used to flavour a wide variety of foods and drinks.