In the festive season up to 75 per cent of revellers will suffer hangovers. This self-inflicted ailment involves a lot of chemistry

The morning after... 

Headache, nausea, tremors and fatigue. Hangover symptoms are caused partly by dehydration - ethanol is a diuretic. A build up of toxins adds to the malaise. Acetaldehyde, from the breakdown of alcohol in the liver is thought to be more toxic than alcohol itself. Impurities in alcohol, congeners, are recognised by the body, which mounts an immune response, similar to that you might get with the flu virus. Finally, poor sleep caused by an alcohol-suppressed brain waking up as the drink wears off adds to the hangover’s severity.  

...the night before 

Apart from not drinking at all, try sticking to highly-distilled sprits like gin and vodka, and more expensive wines, which contain fewer congeners. To let the liver catch up, avoid carbonated drinks and eat protein rich foods, which might help slow the rate of alcohol absorption, and halt the build-up of toxins. Most importantly, stay hydrated. 

A bitter pill to swallow 

Commercial hangover remedies use an absorbant material (like the charcoal slurry used in stomach pumping) to bind congeners in the gut. Evidence of their effectiveness is scarce, and experts say the best thing to do is drink plenty of water, take an aspirin and go back to bed.