(Dec 19) The party's over, the bottles are empty and the room has stopped spinning.

But your head is throbbing, your mouth is as dry as the last bottle of white and moving requires superhuman willpower.

Unlike a party, a hangover takes no planning whatsoever, but there are measures you can take to ease the effects and even prevent one altogether.

What is a hangover?
Hangovers are characterised by headaches, nausea, dizziness, irritability, thirst, fatigue and loss of appetite, explains Dr Lee Chiew from Clinique D'Tox in Camden Medical Centre.

'Hangovers are thought to be caused by an excess of toxins in the blood system. The body cannot process and get rid of them as quickly as required, thus the accumulation - the excess - causes sickness.'

The symptoms of a hangover are then exacerbated by dehydration because alcohol acts as a diuretic. A diuretic reduces the amount of water in the body by encouraging urination.

Curing a hangover

The key to curing a hangover would be to not drink too much in the first place. But, 'once a hangover has kicked in, time is the only cure,' says Dr Lee.

There are, however, ways to at least alleviate the symptoms. She suggests taking aspirin to take care of the headache and to drink fluids to offset dehydration.

British nutrition expert Patrick Holford says in his book The New Optimum Nutrition Bible that once the liver's ability to detoxify alcohol is exceeded, the body produces a toxic substance and it is this that brings about a headache.

His advice for reducing the 'morning after' symptoms is to drink a lot of water to dilute the alcohol and also to eat pure foods that will not add to the body's toxic burden.

Stick to fruit and vegetable juices, which are high in antioxidants, and water.

In a late 2005 issue of the British Medical Journal, researchers studied the effectiveness of hangover cures, but did not find compelling evidence that an effective cure exists. So while some people may swear by certain remedies, is this really another case in which prevention is better than cure?

Avoiding a hangover
In her book The Drinkless Mind, Ms Georgia Foster advocates drinking a glass of water for every glass of alcohol - this will help to dilute the effects of the alcohol and may help you feel fuller and therefore less likely to overdo it.

She says: 'If you forget this tip when you're out, then drinking as much water as you possibly can when you get home really does reduce that awful feeling of dehydration when you wake up in the morning.'

Dr Lee suggests that, if you smoke, you should cut down while out drinking. Smoking makes you thirsty and that is only going to encourage a hangover - unless the drinking is non-alcoholic.

Avoid drinking on an empty stomach. Food helps to absorb alcohol, giving the body more time to process it and reducing the risk of a hangover.

'Eating foods high in protein - such as fish, nuts and beans - before drinking is thought to slow down the alcohol absorption rate,' adds Dr Lee.

As far as alcohol goes, some types are more toxic than others. Alcohol itself contains toxins, which are the by-products of fermentation and distillation. These toxins are called congeners. Some drinks have more congeners than others, explains Dr Lee, because of the way they are fermented.

Darker drinks, such as red wine, brandy and port, have more congeners than white wine, gin or vodka.

The bubbles in champagne speed up the absorption of alcohol into the bloodstream.

Barman mixes his own hangover 'cure'
Mr Calven Khoo (above with his 'cure'), bar manager at Prime Society restaurant on Dempsey Hill, has a decade of experience and has come across various remedies for hangovers.

He says: 'Drinking citrus juices, popping Vitamin C tablets and drinking coffee all have certain effects, but they do not address the problem completely.

'I use bottled jasmine green tea to help detox the liver, honey to provide energy and oranges for their Vitamin C content.'

Combining all these ingredients, says Mr Khoo, is the ideal hangover cure. And it is simple to make too.

Ingredients
120ml green tea
45ml orange juice
One tablespoon honey
Two slices of orange

Method
Place the slices of orange in a glass. Mix all other ingredients together and pour into the glass with the sliced orange.

Other ways to sober up
There are some weird and wonderful supposed hangover cures at www.hungover.net. Here is a selection of the more 'normal' ones:

Isotonic drinks
Your body will be lacking in salts, so replenish with a sports drink such as Gatorade. The liquid refreshment will help your hangover too.

Sugar
Your body needs sugar to break down alcohol, so munch on a chocolate bar.

Juice
The water in juice rehydrates the body, and the fructose (sugar) it contains helps burn up the alcohol.

Kudzu
A close to nature remedy is the Chinese vine Kudzu. It has been used for curing hangovers since 200BC.

Ginkgo
Ginkgo seeds contain an enzyme that speeds up the body's metabolism of alcohol.

Supplement
Before going to bed, drink two glasses of water along with Vitamin C and B capsules. The vitamins help to clear alcohol from the bloodstream.