Although not an item that can be used (except in context sensitive situations), beer is the reason Conker got himself into his bad fur day troubles. At the beginning of the game, Conker spends most of the night drinking with some of his soldier buddies (one of whom is presumably Rodent) who have to go to war, which Conker uses as an excuse to stay out and drink. After a few good drinks, Conker has had enough for the night, says his goodbyes to his buds, and staggers his drunken self out of the tavern, when which he then empties his stomach on the cobblestone street, right next to a distressed Gobling.
Conker also gives a beer to Birdy, the less-then-scary scarecrow, in the beginning gameplay of the game, when Birdy teaches Conker about Context-Sensitive Pads. Conker can drink beer in some chapters, allowing him to urinate as well as vomit.