While scientists puzzle over what causes some people but not others to get migraines, there's no mystery about hangovers.
There's only one cause: excessive drinking.
And one sure prevention: not drinking.
"Alcohol is a toxic substance to many tissues of the body, and in hangovers, it's toxic to the brain and the lining of the stomach," said Dr. Kevin Ferentz, assistant professor of family medicine at the University of Maryland School of Medicine.
That, he said, explains the pounding headache and nausea that can strike a New Year's reveler just hours after putting down his or her last drink. Abstinence is the best prevention, but he said it also helps to space one's drinking across the evening, to mingle food with alcohol and to drink plenty of water.