Alcohol stops the body making vasopressin, a hormone that allows the body to absorb water. So when you drink, it all goes to the bladder, leading to lots of urination and then dehydration. You're literally emptying yourself of water and the vitamins and minerals it carries around your body. This includes most of your glycogen, the compound that stores your body's energy.
'Handover' only got its modern, alcohol-related meaning in 1904. It originally meant 'unfinished business'. Before, if you were sick from too much drinking you were 'crapulous'. The medical term of a hangover is veisalgia, from the Greek algia, meaning pain, and the Norse word kveis, meaning 'uneasiness after debauchery'.
How does it feel?
In German, to have a hangover is einen kater haben, 'to have a tom-cat' or katzenjammer, meaning 'the wailing of cats'. To Norwegians, it's jeg har tommermen, 'I have carpenters' (in my head, presumably) and for the French it's avoir la gueule de bois, 'to have a wooden throat'.
The Italians, who don't like getting drunk, opt for the bland postumi di shornia, 'the effects after drinking'.
What can you do?
According to the Student British Medical Journal you can partially avoid getting a hangover by drinking lots of water during the evening or not drinking on an empty stomach. However, once you have one, there is very little you can do to make it go away. The only certain way to avoid a hangover is to avoid drinking. That hasn't stopped people trying.
Many countries offer their own variation on tripe soup, with Mexico's fiery hot pancita and Korea's haejangguk or 'soup for the stomach' containing cow bones and blood. Sicilians have touted dried bull's penis, while tea brewed with rabbit droppings was supposedly a favourite of American cowboys.
The Roman statesman Cato recommended raw cabbage in vinegar. Pliny the Elder suggested raw owl's eggs or fried canary. European doctors in the Middle Ages thought raw eel and bitter almonds might work. To cure hangovers, Mongolians supposedly used to eat pickled sheep's eyes. Germans still like to eat katerfruhstuck ('tom-cat-breakfast'), a meal that often involves herring, pickles and goulash.
Hair of the dog?
The idea of drinking again the next morning called in full 'the hair of the dog that bit you' (a reference to a supposed remedy for rapid dog bite), really just postpones the hangover. Caffeine may perk you up, but it's adiuretic and can further upset a delicate stomach.
The prarie oyster involves a raw egg with Worcestershire sauce, Tabasco, and perhaps some alcohol, to be consumed in one swallow (Jeeves made them for Wooster: 'Gentlemen have told me they have found it extremely invigorating after a later evening'). In Thunderball, James Bond says: 'There wasn't a week went by but that on at least one day I couldn't eat anything for breakfast but a couple of aspirins and a prairie oyster.'
Kingsley Amis, the hard-drinking writer, believed in the 'metaphysical hangover', that empty feeling of sorrow and self-loathing. One theory is that this is due to alcohol reducing the level of neurotransmitters called gamma-Aminobutyric acid (or GABA) in our brain. The right GABA level is linked to relaxation and feeling happy. Too little GABA makes us anxious, depressed and unable to sleep.
Does it matter?
According to William of Malmesbury, the Battle of Hastings was lost because the Saxon army had hangovers: 'The English passed the night drinking and singing, the Normans passed the whole night in confessing their sins, and received communion in the morning.'
Complied by Molly Oldfield and John Mitchinson