When you get drunk,
the ethanol decays in your system through other forms of alcohol until it is all gone. The other forms of alcohol are a bit more poisonous and give you the classic headache and sick feeling, which eventually disappears as these other alcohols are broken down. Some drinks have more of these other kinds of alcohol in them to start with, so give you worse hangovers. Your body only breaks them down slowly while you are drinking due to the ethanol levels. That's why Hair Of The Dog works - drink more in the morning and you stop your body poisoning you.

Science.
(MrOli is ugly, but in the morning you will be sober, Sat 4 Jun 2011, 15:05, 2 replies, latest was 14 years ago)

Interesting
But I just like beer.
(robneymcplum spiced up his life on, Sat 4 Jun 2011, 15:45, Reply)

Fair enough :-)
Keep Drinking and Carry On!

But a tiny bit more Science! for this tip: Because of the alcohol slowing down your body's ability to break down alcohol, you should always start counting the "1 unit broken down per hour" (or whatever that very rough rule of thumb is) from the time you last had a beer.
(MrOli is ugly, but in the morning you will be sober, Sat 4 Jun 2011, 17:47, Reply)

Aye,
I drink 140+ units a week so the odd unit is neither here nor there.
(robneymcplum spiced up his life on, Sat 4 Jun 2011, 17:54, Reply)

I thought the headache
was caused by dehydration. Which is why after a night on the sauce, I have a cup of tea before going to bed and taking a big glass of blackcurrant squash up with me to drink if I wake up thirsty.

With that, I've not had a hangover in years.
( sandettie light vessel automatic New Twitter - @bollocksreally, Sun 5 Jun 2011, 22:07, Reply)

Well, it's a little of each, I think...
To be honest, I'm hoping to be corrected on the Science! bit, it's just how I had it explained once and I may have misunderstood.
(MrOli is ugly, but in the morning you will be sober, Sun 5 Jun 2011, 22:58, Reply)