Gf made food with chicken broth that's been opened (but with closed lid) and sitting in the cupboard. Worried about getting sick.. please help

Does she remember using it and sticking it back in the cupboard? I will say that the new cartons of chicken broth have a newer style of safety seal that you just turn and click open. There is no little piece of foil you peel back like the old days. It took a few cartons for me to understand that I wasn't actually getting a carton that had been previously opened. Maybe the same happened for your GF? In any event, she should NOT have used it if she wasn't certain and she absolutely should have told you. That would be a deal breaker for me.

If you're not feeling sick, you'll probably be all right--but if you begin to feel queasy later on, I'd get to some sort of health care center. Seriously, using something that has been improperly stored is simply not bright. But even more concerning is that this woman knew you would object and tried to deceive you. That is not the basis for a good relationship. Ever.

How long had it been opened? It probably had a high salt content, which might retard spoilage, but I certainly wouldn't want to use it or eat it. Get another girl friend!