When i eat spicy foods (big fan of vindaloos) i get an upset stomach the next day (and the usual unpleasantness that follows). Is there a magical cure that means i can continue to enjoy spicy foods without the inevitable consequences, like a glass of milk or an antacid?

It might not be the spiciness, but rather the grease and fat(especially if the food you're eating is from some hole in the wall restaurant).

Then again, some people just react that way to spicy food. Antacids might help for a little temporary relief.

Maybe try an OTC flatulence preventative(Beano is the one I'm familiar with just because of the commercials).

If you're eating Indian food, it might be better for you to eat as they do with a Lassi, youghourt will definately prevent that annoying feeling in the stomach, just order a mango lassi instead of beer.