The vine spells cure and cure poison will do the trick
. Or you could drink the yellow colored potions that you can buy in town and find around the place. In the Serpent Temple, you will get to a point where you will 'make' a certain yellow potion (spider nectarine), but
do not drink it. It has the ability to cure poisons as well, but you'll need it towards the end of the serpent temple, so hold on to it.