Our cat was fine until we use a Hartz Flea collar on her then she had twitching similar to seizures. She would often twitch and we removed the collar within 24 hours of noticing the effects. She had mini-seizures ever since and would vomit food several timex weekly and then sometimes daily. Finally we had to have her put to sleep, she never recovered from what we believe to be the toxic repercussions of using the Hartz flea collar. It’s disgusting this company is even in business.