For Christmas revellers it is sobering news. There are scores of hangover cures advertised on the internet, from Dr Ralph's Monday Medicine to Nux Vomica, a homoeopathic remedy that claims to do just what it says on the tin. But few if any of them work, researchers say.

The authors of a study in the British Medical Journal said: "No compelling evidence exists to suggest that any complementary or conventional intervention is effective for treating or preventing alcohol hangover."

Taking a couple of paracetamols and a pint of water before bed is too simple for most seeking relief from a night's hard drinking. Bananas, barley grass, cabbage, charcoal tablets, eggs, exercise, green tea, hair of the dog (more alcohol), kidney dialysis, milkshake and Vegemite on toast are among recommended remedies.

A search of the medical literature revealed 15 trials of hangover cures, from the blood pressure drug propanolol to a herbal treatment containing extract of artichoke. Most of the trials, which tested eight agents in all, showed no beneficial effect. However, the researchers, led by Edzard Ernst, professor of complementary medicine at the University of Exeter, found encouraging results for borage, a herbal remedy with anti-inflammatory properties, a product based on dried yeast called Morning Fit and tolfenamic acid, a painkiller. Professor Ernst said a major problem preventing development of an effective cure for hangovers was the lack of information about the effect of alcohol on the body.

"We don't understand the mechanism of what a hangover is. We know it has to do with the toxic effects of alcohol and dehydration but we don't know how it works."

One trial suggested that alcohol acts on the synthesis of the hormone prostaglandin, a theory supported by the beneficial effect of tolfenamic acid, a potent inhibitor of prostaglandin synthesis.

Research on hangover cures was inhibited by ethical concerns because success could induce heavier drinking.

However, no evidence has shown that the threat of a hangover deters drinking. Professor Ernst said: "Whether there is a cure or not, the fact that you suffer from a hangover means your body is telling you that you have been poisoned. And you have done it to yourself.

"So many people would be outraged if they had been poisoned in that way by someone else."

How to minimise the after-effects of drinking

* Go to bed

* Play in the hay. Sex gets the blood pumping and your body rehydrating

* Drink plenty of water - alcohol is a diuretic stimulating the kidneys to produce more urine

* Take a long shower

* Get a sugar hit - a chocolate bar, perhaps - to break down the alcohol

* Try a sports cordial drink - packed with rehydrating salts

* Drink a strong coffee - it will reduce the swelling of the blood vessels in the brain