Edit: Oh. Hydrocortizone...is technically a medication. Not all that dangerous, actually. Still, you should call poison control, but it's not like she's going to keel over and die in the next few seconds.
Tell her next time food poisoning should suffice. I suggest expired milk. Or milk left our for a couple hours. Nasty to eat but hey, better than toxic chemicals.
According to the stuff I can dig up on a quick basis, the stuff's a hormone designed to raise blood pressure and blood sugar levels. It's supposedly not poisonous, or at least not poisonous enough for there to be a big concern about it, as both my searches of Poison Control and the web in general turn out no negative results. It's normally used for dealing with poison ivy.
(Sources: http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC33091)
Nonetheless, feel free to scold her. Having a bad feeling is no reason to make yourself sick besides, you don't need to ingest poison to make yourself ill, most people can do that out of sheer willpower.
EDIT: Seems like Crowley's already got you covered. I'll leave this up for your spare time curiosity then.