If you have to give your rats oral medication, try to maintain that they willingly take the medicine. If you have to force your rat to take it then they are likely to never willingly take it again. This is a testament to just how easy it is for a rat to be conditioned to never eat food they have a bad experience with, even if it was only 1 bad instance
(Don't worry, it's not neurological, he's fine, he's just a dingbat who doesn't like his tail being wet but insists on dunking his tail in the water dish so then he tries to grab it to dry it off while still in the water. He dum.)