Whiskey

 is a food item found in Fallout 3 and Fallout: New Vegas.

Fallout 3
Drinking it increases strength one point, which allows you to temporarily carry 10 extra pounds of items. By drinking this you run the risk of addiction, curable by doctors for a fee. It also boosts your charisma by 1 point while lowering your intelligence by 1 point.

Whiskey has all the same effects as vodka and beer. It is cheaper than vodka and found more often around the Wasteland.

Fallout: New Vegas
Whiskey is also a consumable item in Fallout: New Vegas

General
Whiskey provides the same base effects as in Fallout 3, increasing Charisma and Strength by 1 while reducing Intelligence by 1.

As with any consumable item in Fallout: New Vegas though, whiskey's effects (both positive and negative) are altered by the player's Survival skill, including the DT increase provided by the Whiskey Rose perk (see below). With a Survival skill of 100 you receive +3 to Charisma and Strength, -3 to intelligence and +6 to Damage Threshold with the Whiskey Rose perk.

In Hardcore mode Whiskey also increases your level of dehydration so that you have to drink more water. Again this effect is increased by higher levels of Survival skillgoing from +25 at lower levels to +75 at 100 Survival skill.

Whiskey Rose
Whiskey Rose is a perk provided while having the npc companion Cass in your party. The penalty to Intelligence for consuming whiskey is eliminated and it also provides a 2-6 point increase (based on your Survival skill level) to the player's Damage Threshold.

Variants

 * Dixon's Whiskey is a variant sold by Freeside merchant Dixon. It provides no Charisma boost and a penalty of 2 to Intelligence, and also has a high 50% addiction rate.
 * Irradiated Whiskey is, as the name indicates, radioactive. It provides the same effects as Whiskey with an added 10 points of radiation.  It can be found reliably in one place: the Camp Searchlight Fire Station, three bottles located in the kitchen.  A fourth bottle may rarely be found in the refrigerator inside Hell's Motel.

Both variants do not provide any increase to Damage Threshold when the player has the Whiskey Rose perk, though their penalties to Intelligence are still negated.