It's New Year's Eve, so here's our PSA: Drink responsibly. If you are drinking, don't drive—take a cab, take mass transit (subways and buses are running on a Sunday schedule), and the Department of Transportation is even handing out $15 Taxi card and single-ride Metrocards today at 5 p.m. on the Upper East Side and in Harlem—and drink water!

When we tried out a few alleged hangover cure-alls, we asked Dr. Jason Rosenberg, assistant professor of neurology and the director of the Johns Hopkins Headache Center, why drinking so much hurts so bad.

"You're basically poisoning yourself when you drink alcohol to excess and there's not a great antidote for it."

"Nerves that are normally quiet that don't respond to light, noise, movements, your own heartbeat—they get revved up," says Rosenberg. "They're firing pain signals, so that you can feel every beat of your heart. Boom. Boom. Boom." Dr. Rosenberg posits that these nerves are largely responsible for the torture. "Nearby systems kind of get kicked off either reflexively or directly from the alcohol's toxins that cause nausea." And what about profuse sweating and piercing hatred of the sun? "A whole variety of reflexes might get kicked up too: light sensitivity, sweating, other non-specific responses."

Dr. Rosenberg noted that there wasn't a whole lot that can be done to immediately alleviate the symptoms of a hangover—when you've got it, you've got it. It's easier to prevent one, presumably by not drinking as much.

That said, Dr. Rosenberg says the best thing to do is to drink water, "Know your limits, stay hydrated, eat while you're drinking. Do it responsibly and make sure you get some sleep." Other things to keep in mind: Don't drink on an empty stomach and don't go in the steam room.