User blog comment:Uncleho/Perhaps this is how Arthur learns of Merlin's magic?/@comment-5204542-20121118171348

Its possible but I think they are going to wait until the series finale to show the reveal. Maybe Gaius will cover up for Merlin using magic on Gwen and says that he gave her a potion or something. Or perhaps Merlin cures Gwen by turning into Old Merlin.