[pyre]

  | she could do somewhat better than the locals

I get what you're saying, but I think that 'somewhat better' is an understatement. Obviously she's not going to be performing heart transplants and bi-pass surgeries, but just knowing about things like penicillin, would be huge (not to mention knowledge of things like disease vectors, etc).

[csomar]

I would actually say "she probably knows less than the locals and can do much less than the locals".

I studied Medicine for two years, and was surprised by how much advanced and knowledgeable our ancestors were.

Pharaons did brain surgery to remove cancer tumors a thousands years back successfully. This alone, shows the degree of sophistication and technology they had.

Now I'm not saying before is better, but today we rely a lot on technology (IRM, Radiology, Echography...) that we don't keep much of the details and don't even need to learn them.

[pyre]

Well, then depends on the part of the world and the period. I was assuming 15th century Europe, which is a different story. Also, things like penicillin have a much broader affect than removing a couple of brain tumors. On the other hand, advanced knowledge could be called witchcraft, and she could be burned at the stake.