Here are tips on preventing a hangover:

• Drink slowly and on a full stomach. Keep in mind that if you are a small person, the effects of alcohol consumption are greater on you than on a larger person.
• Drink only in moderation. The National Institute on Alcohol Abuse and Alcoholism recommends that women have no more than 1 drink per day and men no more than 2 drinks per day. One drink is defined as a 12-ounce bottle of beer, a 4-ounce glass of wine, or a 1 1/2-ounce shot of liquor.
• Drink a glass of water in between drinks containing alcohol. This will help you drink less alcohol, and will also decrease the dehydration associated with drinking alcohol.
• Avoid alcohol completely to prevent hangovers.

If you have a hangover, consider the following for relief:

• Consume foods and drinks that contain fructose (such as fruit juice or honey). There is some evidence that fructose will help your body burn the alcohol faster -- that is, get the alcohol out of your body faster.
• Eat well, if possible. Bouillon soup is good for replacing salt and potassium depleted by drinking alcohol.
• Get plenty of rest. Most hangovers are gone within 24 hours. Remember, even if you feel good the morning after heavy drinking, the residual effects of alcohol will diminish your ability to perform at your best.
• Avoid taking any medications for your hangover that contain acetaminophen (such as Tylenol), because it may cause liver damage when combined with alcohol.

Pittler MH, Verster JC, Ernst E. Interventions for preventing or treating alcohol hangover: systematic review of randomised controlled trials. BMJ. 2005;331:1515-1518.

Xu BJ, Zheng YN, Sung CK. Natural medicines for alcoholism treatment: a review. Drug Alcohol Rev. 2005;24:525-546.