A bitter aromatic bark, obtained from a South American tree of the rue family (Galipea cusparia, or Galipea officinalis). It is used used as a tonic, in medicines, liqueurs and bitters.
The most popular brand of cocktail flavoring bitter, containing rum and gentian. See Bitters and See Gentian Liqueur.
Alcoholic bitter (44%) based on Rum and named after the Venezuelan city where it was fist produced in 1824. Because it is very concentrated, a few drops will be enough to bring a cocktail to taste.