Mushroom Vodka is the main drink of choice in the Metro system. 'Shroom Vodka is distilled in large quantities in settlements, and traded throughout the Metro system by the factions and settlements that make it. It is known to be a major export of Exhibition Station.
It is found almost in every place populated by humans, and is one of the only alcoholic beverages available for people to drink since mushrooms are available everywhere in the Metro. Although some pre-war alcoholic beverages can be found, these are (obviously) very rare in the game's present time. 'Shroom Vodka tastes horrible and "Knocks you on your ass", but it is one of the few luxuries people in the Metro have left.
After completing the Chase level, Artyom, Boris, and Eugine get some R&R at Riga station's bar, drinking 'Shroom Vodka shots in Artyom's honor for saving their lives. In market station, Artyom can drink Vodka for free.