Żubrówka Bison Grass Vodka is a flavored Polish vodka liqueur, which contains a bison grass blade (Hierochloe odorata) in every bottle. The Żubrówka brand name is also used on bottles of conventional vodka, labeled as Żubrówka Biała. An easy way to tell the difference is to look for the blade of grass in the bottle. The grass is sourced from the Białowieża Forest, hand-picked and dried under natural conditions.