The most obvious and easy thing I can think of is Penicillin. If you can somehow identify which moldy bread is it, that with the basic knowledge of human healt

The most obvious and easy thing I can think of is Penicillin. If you can somehow identify which moldy bread is it, that with the basic knowledge of human health any modern person should have, will make a great healer. This is a time when people were still sealing wounds with boiling oil. So yes, even if you have no formal first aid training you can be a great healer.