Alcohol is a diuretic (meaning it removes fluids from the body), so drinking excessively can lead to dehydration.

Dehydration is what causes many of the symptoms of a hangover.

As well as dehydration, alcohol can upset your stomach and give you a bad night's sleep.

You may even wake up and still have some alcohol in your system the next morning delaying the onset of hangover till later that day. This means you may not be safe to drive or engage in at risk behaviour like working with machinery.

Myths about hangover cures

Hangover cures are generally a myth. There are no cures for a hangover. There are tips for avoiding a hangover and for easing the symptoms if you have one.

The best way to avoid a hangover is not to drink. If you decide to drink, do it sensibly and within the recommended limits.

Drink water or non-sparkling soft drinks in between each alcoholic drink.

To minimise the risk of future serious health problems, men and women shouldn't regularly drink more than two standard drinks a day.

To avoid a hangover, don't drink more than you know your body can cope with. If you're not sure how much that is, be careful.

Know your standard drinks

Working out exactly what a standard drink is can be tricky. In a nutshell, one standard drink contains 10g of pure alcohol (equivalent to 12.5ml of pure alcohol), regardless of glass size or alcohol type (such as beer, wine or spirits).

For example, a 250ml can of high strength pre-mix spirits (7-10% alc. vol) equals 1.4-1.9 standard drinks, while a 285ml glass of full strength beer (4.8% alc. vol) equals 1.1 standard drinks. Therefore, these two drinks represent almost three standard drink measures according to their alcohol content. This is why you must measure standard drinks by the amount of alcohol they contain, and not by the number of glasses that you consume.

In Australia, all bottles, cans and casks containing alcoholic beverages are required by law to state on the label the approximate number of standard drinks they contain.

Once you know how much alcohol a standard drink contains, you can keep track of what you're consuming. You may be surprised a couple of glasses of wine can quickly add up to a lot more than you intended to drink.

More information on standards drinks can be found at www.alcohol.gov.au or www.nhmrc.gov.au.

Tips to avoid hangover

Follow these tips to keep hangovers away:

• Don't drink on an empty stomach. Before you go out, have a meal that includes carbohydrates (such as pasta or rice) or fats. The food will help slow down the body's absorption of alcohol.
• Don't drink dark-coloured drinks if you've found that you're sensitive to them. They contain natural chemicals called 'congeners' (impurities), which irritate blood vessels and tissue in the brain and can make a hangover worse.
• Drink water or non-sparkling soft drinks in between each alcoholic drink. Carbonated (sparkling) drinks speed up the absorption of alcohol into your system.
• Drink plenty of water before you go to sleep. Keep a glass of water by the bed to sip if you wake up during the night.

The morning after

If you wake up the next morning feeling terrible, you probably didn't follow this advice. Although there are no real cures for hangovers, there are ways to ease the symptoms.

Treatment involves rehydrating the body so it can deal with the painful symptoms (though the best time to rehydrate is before going to sleep).

Over-the-counter painkillers can help with headaches and muscle cramps. Paracetamol-based remedies are usually preferable, as aspirin may further irritate the stomach and increase nausea and sickness.

Sugary foods may help you feel less trembly. In some cases, an antacid may be needed to settle your stomach first.

Bouillon soup, a thin vegetable-based broth, is a good source of vitamins and minerals, which can top up depleted resources. Its main advantage is that it's easy for a fragile stomach to digest.

You can replace lost fluids by drinking bland liquids that are easy on the digestive system, such as water, soda water and isotonic drinks (available in most shops).

'Hair of the dog' (drinking more alcohol) does not help. Drinking in the morning is a risky habit, and you may simply be delaying the appearance of symptoms until the alcohol wears off again.

If you've had a heavy drinking session, hangover or not, doctors advise that you wait 48 hours before drinking any more alcohol, in order to give your body tissues time to recover. Sometimes, of course, a hangover makes that advice easier to follow.

Sources: Department of Health and Ageing, Cth (Standard drinks guide), NHS Choices, UK (Hangover cures)