If you have a hangover, it’s because you drank too much alcohol in a short time, and that hurts your body. Too much alcohol makes your liver work harder, drops your blood sugar, and can make it harder to fight off infections.  Your sleep is disrupted, too, because you wake up more often, and the overall quality of your sleep is reduced.

The number of drinks it takes to cause a hangover depends on your age, gender, ethnicity, and size. For most men, five to eight drinks will do it. For most women, three to five. But the effects can vary widely among different people, so be aware of your own limits. How fast you drink also matters. It takes the liver about one hour to process 1 ounce of alcohol.

If you've ever felt thirsty after a few cocktails, you know that drinking alcohol dehydrates. Hangover symptoms like headache and general malaise are caused by this dehydration. Alcohol makes you urinate more, so you dry out. The more nonalcoholic fluids you drink, the better you'll feel. Sipping water between cocktails will keep you hydrated and slow down your drinking. In the morning, drink water or juice. Chicken soup or sports drinks may also help.

In general, pound for pound, women's bodies have less water to dilute alcohol, and more alcohol gets absorbed into the bloodstream. So a woman can drink less than a man and still get a man-sized hangover. And a woman who drinks heavily is likely to develop alcohol-related organ damage sooner than a man would, even if she drinks less. So stick with one drink a day or less. And remember that SUV-sized cocktails don't count as one drink.

Darker liquors -- such as whiskey, red wine, tequila, and brandy -- generally hit you faster and cause worse hangovers than white wine, beer, or clear liquors such as vodka or gin. This may be because dark liquor contains more congeners, which flavor and color it. But that isn't a free ride to guzzle clear liquor. You can still get a hangover.

The kind of mixer you drink also affects how you will feel the next day. Some people think sugar makes a hangover worse. But sugar actually slows the absorption of alcohol. So, a sugar-containing liquid is a safer choice as a mixer than diet drinks.

When it comes to hangovers, your body doesn't care whether you drink liquor or beer first. How much you drink and how fast are what counts. Whether it's a 12-ounce beer, a 5-ounce glass of wine, or a 1.5-ounce shot of liquor, you're getting about the same amount of alcohol. However, people tend to drink mixed drinks and shots faster than beer. So if you switch from liquor to beer, you may be likely to drink less overall.

There's no evidence that eating anything after drinking is helpful. But eating before and while drinking can help reduce and slow the absorption of alcohol.  Having food in your stomach keeps alcohol from going directly into the small intestine, where it is absorbed into your bloodstream. High-protein foods, like cheese, are best at slowing down the effects of alcohol, and thus help prevent a hangover. But drink on an empty stomach and you could black out.

Taking a pain reliever before bed is not a good idea. It taxes your liver, which is already overtaxed from drinking. And it will wear off by morning, so it won't do much good when you really need it. Instead, take a pain reliever when you wake up, if you need. Avoid acetaminophen, which can cause dangerous liver swelling and damage. Ibuprofen or aspirin are better choices because they don't damage the liver, although they may irritate your stomach and increase the risks of ulcers. Drinking water before, during, and after drinking alcohol also helps.

A drink or two before bedtime may help you fall asleep faster. But as the alcohol in your blood falls, you’re likely to wake often and have trouble falling back asleep. This makes you feel worse the next day. If you have insomnia, relying on a nightcap to fall asleep can also make you run the risk of becoming dependent on alcohol.

Coffee will dehydrate you more, but if you're used to a morning cup, you could have one to avoid a worse headache from caffeine withdrawal. Skip the morning mimosa though. It just postpones the worst hangover symptoms. Complex carbohydrates -- like whole grain toast and crackers -- may counter low blood sugar and relieve nausea.

Herbal remedies for hangovers abound. The scientific evidence to back them up doesn't. A 2004 study did show that taking prickly pear extract five hours before drinking alcohol can relieve nausea, dry mouth, and lack of appetite in some people. But experts say that not enough studies have been done to show conclusively that any herbal remedies work.

Overindulging in alcohol is called intoxication for a reason. Alcohol is a toxic substance. Alcohol poisoning -- when you have too much alcohol in your blood -- can occur with activities including chugging, funneling, doing shots, or drinking liquor-loaded cocktails. And that can cause permanent brain damage, stop your heart or breathing, or make you choke on your own vomit. Danger signs include:

• Vomiting
• Seizures
• Mental confusion, stupor
• Slow or irregular breathing
• Low body temperature, bluish skin, and paleness

If you pass out, you won't just "sleep off" these symptoms. You need emergency medical help.

Repeated heavy drinking can weaken your heart and cause strokes and liver scarring, known as cirrhosis. It also can raise your risk for some cancers and create problems with memory, sleep, and mood. Some of these changes are reversible, however. If you are a heavy drinker, quitting can lower your risk for cancer, correct some brain changes, and stop liver damage from progressing.