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Hangover symptoms typically begin when your blood alcohol drops significantly and is at or near zero. They're usually in full effect the morning after a night of heavy drinking. Depending on what you drank and how much you drank, you may notice:

• Fatigue
• Thirst
• Headaches and muscle aches
• Nausea, vomiting or stomach pain
• Poor or decreased sleep
• Increased sensitivity to light and sound
• Dizziness or a sense of the room spinning
• Rapid heartbeat
• Red, bloodshot eyes
• Shakiness
• Decreased ability to concentrate
• Mood disturbances, such as depression, anxiety and irritability

When to see a doctor
Hangovers go away on their own. Talk with your doctor if you're concerned that frequent, heavy drinking or hangovers are affecting your quality of life, including your personal relationships or your performance at work. Treatment for alcohol abuse or dependence is available.

More-severe signs and symptoms that accompany heavy drinking may indicate alcohol poisoning — a life-threatening emergency.

Call 911 or your local emergency number if a person who has been drinking steadily develops:

• Confusion or stupor, as if in a daze
• Vomiting that persists
• Seizures
• Slow breathing (less than eight breaths a minute)
• Irregular breathing
• Blue-tinged skin or pale skin
• Low body temperature (hypothermia)
• Unconsciousness — "passing out"

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Hangovers are caused by drinking too much alcohol.

A single alcoholic drink is enough to trigger a hangover for some people, while others may drink heavily and escape a hangover entirely.

Various factors may contribute to the problem. For example:

• Alcohol causes your body to produce more urine. In turn, urinating more than usual can lead to dehydration — often characterized by thirst, dizziness and lightheadedness.
• Alcohol triggers an inflammatory response from your immune system. In particular, your immune system may trigger certain agents that commonly produce certain symptoms, such as an inability to concentrate, memory problems, decreased appetite and loss of interest in usual activities.
• Alcohol irritates the lining of your stomach. It increases the production of stomach acid and delays stomach emptying. Any of these factors can cause abdominal pain, nausea or vomiting.
• Alcohol can cause your blood sugar to fall. If your blood sugar dips too low, you may experience fatigue, weakness, shakiness and mood disturbances, even seizures.
• Alcohol causes your blood vessels to expand, which can lead to headaches.
• Alcohol can make you sleepy, but your quality of sleep will decrease. This may leave you groggy and fatigued.
• Alcoholic beverages contain ingredients called congeners, which give many types of alcoholic beverages their flavor and which can contribute to hangovers. Congeners are found in larger amounts in dark liquors, such as brandy and whiskey, than in clear liquors, such as vodka and gin.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Anyone who drinks alcohol can experience a hangover, but some people are more susceptible to hangovers than are others. A genetic variation that affects the way alcohol is metabolized may make some people flush, sweat or become ill after drinking even a small amount of alcohol. Research hasn't clearly shown whether light drinkers or heavy drinkers are more likely to experience hangovers. Frequent drinkers may build up a tolerance that decreases their risk of hangovers.

Factors that may make a hangover more likely or severe include:

• Drinking on an empty stomach. Having no food in your stomach speeds the body's absorption of alcohol.
• Using other drugs, such as nicotine, along with alcohol. Smoking and drinking together appears to increase the likelihood of next-day misery.
• Not sleeping long or well enough after drinking. Some researchers believe that some hangover symptoms are often due, at least in part, to the short and poor-quality sleep cycle that typically follows a night of drinking.
• Having a family history of alcoholism. Having close relatives with a history of alcoholism may suggest an inherited problem with the way your body processes alcohol.
• Drinking darker colored alcoholic beverages. Darker colored drinks often contain a high volume of congeners — the chemicals used to add color and flavor to alcohol. Congeners are more likely to produce a hangover.

Drinks with a high congener content include:

• Bourbon
• Scotch
• Tequila
• Brandy
• Dark-colored beers and beer with high alcohol content
• Red wine

By comparison, drinks with a lower congener content — such as lighter colored beers, gin and vodka — are somewhat less likely to cause a hangover. However, while lighter colored drinks may slightly help with hangover prevention, drinking too many alcoholic beverages of any color will still make you feel bad the morning after.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

When you have a hangover, you're likely to experience problems with your:

• Memory
• Concentration
• Dexterity
• Visual-spatial skills, or your ability to accurately perceive how objects you're looking at relate to each other in space around you

Not surprisingly, this temporary dulling of your abilities increases your risk of a number of problems at work, including:

• Trouble completing your tasks
• Criticism from a supervisor
• Conflict with co-workers
• Falling asleep on the job
• Workplace injuries

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Time is the only sure cure for a hangover. Here are a few things you can do to help yourself feel better in the meantime:

• Fill your water bottle. Sip water or fruit juice to prevent dehydration. Resist any temptation to treat your hangover with more alcohol. It'll only make you feel worse.
• Have a snack. Bland foods, such as toast and crackers, may boost your blood sugar and settle your stomach. Bouillon soup can help replace lost salt and potassium. Foods and drinks that contain fructose, such as honey or fruit juice, may help your body burn the alcohol faster.
• Take a pain reliever. A small dose of an over-the-counter pain reliever may ease your headache. But there are a few caveats. Aspirin can irritate your stomach. And if you sometimes drink alcohol to excess, acetaminophen (Tylenol, others) can cause severe liver damage even in doses previously thought to be safe.
• Go back to bed. If you sleep long enough, your hangover may be gone when you awaken.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

From stimulating your scalp with hair pulling to drinking sauerkraut juice, proposed alternative remedies for hangovers abound. Studies haven't found any natural remedies that consistently improve hangover symptoms. Still, some vitamins and herbs may help your body clear toxins, including:

• B vitamins
• Vitamin C
• Evening primrose oil
• Milk thistle (Silybum marianum)
• Globe artichoke (Cynara scolymus)

Talk with your doctor before trying any alternative medicine. Natural doesn't always mean safe. Your doctor can help you understand possible risks and benefits before you try a treatment.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Despite various over-the-counter pills and tablets that claim to prevent hangovers, the only guaranteed way to prevent a hangover is to avoid alcohol. If you choose to drink, do so in moderation. The less alcohol you drink, the less likely you are to have a hangover.

It may help to:

• Eat first. Alcohol is absorbed more quickly if your stomach is empty. It may help to eat something before drinking alcohol.
• Take it slow. Drinking isn't a contest. Pace yourself. Limit yourself to just one drink each hour.
• Choose carefully. Beverages with fewer congeners — such as vodka and gin — are slightly less likely to cause hangovers than are beverages with more congeners — such as brandy and whiskey.
• Sip water between drinks. Drinking one glass of water after each alcoholic drink will help you stay hydrated. It'll also help you drink less alcohol.

Also know your limits. Decide ahead of time how many drinks you'll have — and stick to it. Don't feel pressured to drink.

Some people take over-the-counter pain relievers, such as aspirin or ibuprofen (Advil, Motrin, others), to prevent hangover symptoms. But be sure to ask your doctor if this is safe for you to do and what dosage is best for you. These medications may interact with other medications, and in the case of acetaminophen (Tylenol, others) may cause liver damage if too much alcohol is consumed.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.