Whelan Bitters was an intoxicating beverage.
In 2374, Grathon Tolar consumed a number of bottles of Whelan Bitters at Quark's while on Deep Space 9. Halfway through his fourth bottle he attempted to dance with dabo girl M'Pella, who declined his invitation. A brief struggle ensued in which Quark was stabbed. (DS9: "In the Pale Moonlight")