Alcohol (chemical designation ethyl alcohol or ethanol) is a colorless, liquid chemical, usually the by-product of fermenting sugar. Alcohol is a powerful psychoactive drug with intoxicating effects in humanoids.
Alcohol is often replaced by synthehol, which carries all the properties of alcohol, but without the deleterious effects. When mixed with a theragen derivative, it blocks certain nerve impulses to the brain and can be used to treat the "madness" caused by exposure to interphase. (TOS: "The Tholian Web")
Jean-Luc Picard confiscated an alcoholic liquid called Dresci from Captain Dirgo while marooned on Lambda Paz. He observed that while the alcohol would advance dehydration if consumed, it could be useful as a coolant or disinfectant. (TNG: "Final Mission")
The Borg are known to have a particularly low tolerance for alcohol. Seven of Nine became intoxicated after a single glass of Champagne, leading The Doctor to conclude that the Borg simply "can't hold their liquor." (VOY: "Timeless")
According to Spock, his father's race was spared the dubious benefits of alcohol. Preceding this remark, T'Pol also specifically noted the Vulcan stance on abstaining from wine. (TOS: "The Conscience of the King", ENT: "Breaking the Ice")
List of alcoholic beverages: