A hangover is the after-effect following the consumption of large amounts of one drug or another. In particular, it is most commonly associated with the consumption of alcoholic beverages. For other addictive drugs, the correct terminology is withdrawal, which is a hangover of sorts for some particular drug.

Table of contents
1 The Symptoms
2 The Cause
3 The Cures

The Symptoms

An alcohol hangover is associated with variety of symptoms, including dry mouth, headaches, bloodshot eyes, nausea and vomiting, and sensitivity to light and noise.

The Cause

Hangovers are multi-causal. Ethyl alcohol has a dehydrating effect, which causes headaches, dry mouth, and lethargy. This can be mitigated by drinking plenty of water between and after the alcoholic consumptions. Alcohol is also a metabolic poison, and its impact on the stomach lining probably accounts for the nausea. Another factor contributing to hangover is the conversion of alcohol to acetaldehyde by the liver. This metabolite is probably more toxic than alcohol. Finally there are various nervous effects. The removal of the depressive effects of alcohol in the brain probably account for the light and noise sensitivity. It is also thought that the presence of methanol mixed with the common ethyl alcohol exaggerates many of the symptoms, which probably accounts for the association with dark drinks. The amount of tannin in the drink may also have an effect.

The amount of flavour compounds in the drink will increase the hangover, so a dark beer, or stout, such as Guinness will produce a worse hangover than drinking the equivalent amount of alcohol diluted in water (basically Vodka).

The Cures

Common folk medicine has a wide variety of hangover cures. Indeed there appear to be nearly as many ways of curing hangovers as there are of getting drunk in the first place. Almost all of these hangover cures have one major thing in common, which is that they are nowhere near as effective at curing a hangover as alcoholic drinks are at getting you drunk.

As of 2003, the latest fad hangover cure is a Russian pill, sold in Russia as Antipokhmelin (Anti-Hangover), and marketed as RU-21 in the USA. It is also known as the KGB pill due to its supposed use by the KGB to allow spies to keep a clear head while drinking.