Unicum is a Hungarian herbal liqueur or bitters, drunk as a digestif and apéritif. The liqueur is today produced by Zwack according to a secret formula of more than forty herbs; the drink is aged in oak casks. During Communism in Hungary, the Zwack family lived in exile in New York and Chicago, and Unicum in Hungary was produced using a different formula. Before moving to the US Janos Zwack had entrusted a family friend in Milan with the production of Unicum based on the original recipe. After the fall of communism, Péter Zwack returned to Hungary and resumed production of the original Unicum.
Unicum is regarded as one of the national drinks of Hungary. The production facility offers tours which include a tasting session of the two different varieties (Unicum, and Unicum Plum). Zwack Frissitők is a pineapple-based softdrink. According to the manufacturer, the original Unicum is no longer distributed in the US, having been replaced by Unicum Next (a sweeter, thinner-bodied drink with a more prominent citrus flavour), re-branded as "Zwack".