One of the things I learned one year when my whole family came down with the worst stomach virus we'd ever seen (I dubbed it "The Plague") was that, once dehydrated to a certain degree, nausea is *exceptionally* hard to shake. It's a self perpetuating thing at that point.

More than 3 liters later on an IV drip, and I did not have to vomit any longer. I'd say the best thing for her would be some fluids. If it has to come via drip, so be it. But 36 hours and no fluids to speak of is a major concern.