This is what I found in the internet. I also include information on "How to avoid hangover". Prevention is always better than remedy :-)
A. How to cure hangover:
(1) Drink water as soon as you get up in the morning to rehydrate yourself. If possible, have a sports drink. The electrolytes and nutrients in a sports drink can replenish your body's depleted reserves.
(2) Drink even more water if you plan to have coffee. Caffeine is a mild diuretic and can contribute to dehydration.
(3) Stick to liquids that are at room temperature. Drinks that are excessively hot or cold will be even more of a shock to your struggling stomach.
(4) Take an over-the-counter pain reliever such as aspirin or ibuprofen to relieve a pounding headache or body aches.
(5) Eat easily digestible foods when you're ready. Fresh fruit, toast and water-based soups are all easy on the stomach. Harder-to-digest foods such as eggs and milk can cause stomach problems.
(6) Relax, rest or go back to bed. Allow some time for your body to feel positive effects from your treatments.

Tips & Warnings
(1) Take preventive measures beforehand: Drink responsibly and in moderation. If you've drunk in excess and suspect you'll be hung over the next morning, drink a few glasses of water right before you go to bed.
(2) Rehydrate yourself with liquids that are at room temperature. Drinks that are excessively hot or cold will make your struggling stomach work even more.
(3) Do not take an acetaminophen-based painkiller to relieve symptoms. Combining acetaminophen and alcohol can damage your liver. Consider ibuprofen instead.
(4) If you are an excessive drinker, use caution when taking any over-the-counter painkillers.
This information is not intended as a substitute for professional medical advice or treatment.

B. How to avoid hangover:
(1)Eat before you drink. Starchy carbohydrates such as bread and pasta will slow the absorption of alcohol.
(2) Avoid very sweet drinks that disguise their alcohol content, and avoid mixing different types of alcohol.
(3) Drink water in between alcoholic drinks to prevent dehydration.
(4) Eat hearty food while you are drinking.
(5) FiveDrink another glass of water when you get home.
Tips & Warnings
(1) If you get a really bad hangover, keep track of what you had to drink the night before and avoid it next time.
(2) Avoid aspirin or ibuprofen if you have stomach ulcers or gastritis