Can she keep down plain ol' water? It's likely that she ate something that isn't agreeing with her digestive system. If she can't keep down even water, then she needs to see a vet. Dehydration can be deadly in a hurry.

Got any kaeopecate? (The forumla without tylenol in it) Give her a bit of that if you have it. It may help settle her stomach. I keep a bottle of it on hand at home for occasional bouts of the pukes!

Has she eaten a large dose of fatty food lately(within the last 12 hours or so)--stolen something or got into the garbage? There's a link between an intake of fat and pancreatitis. Pancreatis causes intense vomiting and needs treatment by a vet immediately.

Don't feed her anything until she has gone at least 12 hours without vomitting. Then offer her a very small meal or some rice and hamburger--just a bit. If she keeps that down for another 12, try feeding normally.

If it doesn't stop soon, get her to a vet.