The last time this happened, you swore off overdrinking for good. That plan would have worked. But being someone who loses count from time to time, it was not the plan for you.
Many, many others are in the same boat. A 1992 Danish survey found nearly three-fourths of adults there occasionally suffer hangover headache, making it the most common form of headache reported.
Short of abstinence, is there any way to prevent a headache from too much alcohol? Is there a cure?
There is, indeed, quite a lot you can do, says neurologist Christine Lay, MD, of The Headache Institute, Roosevelt Hospital, in New York City.
Lay and colleague Christina Sun, MD, authored a forthcoming article on this condition in Headache, the journal of the American Headache Society.
Why We Get Hangover Headaches
Hangovers almost always come with a hideous headache. But you don't have to drink too much to get a hangover headache.
Lay says infrequent, light drinkers are more likely than heavy drinkers to suffer such headaches.
"You don't necessarily have to overdo it. Even dipping in just a little bit can cause a headache," she says.
This is because alcohol has both direct and indirect effects that contribute to headache.
The first thing alcohol does is cause dehydration. Alcohol switches off an anti-dehydration mechanism in the body, causing you to urinate more often than you should.
Alcohol also stresses your liver, making it less able to produce glucose. Glucose -- sugar -- is the fuel that drives every cell in you body. Brain cells are particularly susceptible to a shortage of this fuel.
Alcohol also affects the chemicals that cells in your body use to communicate with each other. One of these chemicals is prostaglandin, which regulates the way you feel pain, among other things.
Finally, alcohol has an inflammatory effect, making your blood vessels swell. This is why some people don't have to wait until morning for their headache.
The main indirect effects of alcohol come from a chemical called acetaldehyde, made as your body processes the booze.
This chemical works like a drug, making you sweat and flush, your heart race, and your stomach turn nauseous. If enough acetaldehyde accumulates in your body, you vomit.
Another indirect effect of alcohol is disturbed sleep. This is why it's so hard to "sleep off" a hangover.
"When you drink too much, you feel like going to sleep -- but there is a paradoxical awakening during the night," Lay says. "Alcohol interferes with rapid-eye movement sleep; and people wake frequently. This waking contributes to headache."