Alcohol is a recurring item on LOST and has appeared several time both on and off the island.
While in London in "Homecoming", Charlie was put to work by Tommy to steal something valuable which he could in turn sell to obtain vast quantities of illicit substances. It was in a bar that Charlie met Lucy Heatherton, and spent the night drinking with her.
Shannon apparently spent a year in Paris where she was drinking, and not studying.
Christian also shares a drink with Sawyer in a bar in Sydney while the two talk about suffering.
In "Outlaws", Kate and Sawyer play a drinking game called "I Never" in which the object is to have your opponent drink more than you by getting them to admit to something that you have never done, but are pretty sure they have, if they have, they drink. In the end, they both come to the realization that they have both killed a man.
When Boone is being operated on by Jack in "Do No Harm", Jack requests Kate to obtain Sawyer's entire stash of alcohol. She does so successfully, but later trips and destroys most of the bottles in the process.
Desmond had bottles of alcohol with him on his boat, and also brings some with him onto land and shares a drink with Locke on the beach in "Live Together, Die Alone." Kelvin is also seen drinking merlot in Desmond's flashback.
The DHARMA Initiative also provided alcohol to the Flight 815 survivors when the supply drop was found by the survivors. This is known because Libby mentions to Hurley that she saw Rose and Bernard pull wine from the pallet.