The herb reputedly takes its name from a 2nd century BCE king of Illyria named Gentius, who discovered its ability to reduce fevers. Powerfully bitter, the herb is an essential ingredient of traditional aperitifs and such bitters as Angostura bitters. The customary aperitif is taken about one-half hour before meals, but it has become more of a social expectation rather than a medicinal one.
In medieval times, it was an ingredient of the alchemical brew called “theriac”, a supposed cure-all made according to a highly secret recipe.
It was officially listed in the US Pharmacopoeia from 1820 to 1882.