Hello and welcome to Just Answer!
Yes, suddenly switching a cat or dog's diet can cause vomiting or diarrhea. What was she on before and what did you switch him to?
he was on jelly based cat food, he was given gravy based of the same brand.
Ok. the gravy based may be a bit richer that what he is used to. He is fasting on his own so I would keep him off of food for today. Let him have water. Before you go right back to his normal food you may have to do a brief period of bland food. you can either try cooking up some boiled chicken or you can buy the stage one baby food that is just chicken and chicken broth. It is pasty and easy to digest plus cats usually love it. that will get him eating again and it will be sensitive enough on his system so that it should help with the diarrhea too. if you fast him and he still does not have an appetite then that is when I would recommend a vet visit. I have seen sudden food changes cause a bout of pancreatitis.
thank you i will definitely follow this. I was concerned as neither of the cats drink very much even though we have fresh water available in a number of rooms and i didn't want him to become dehydrated
I would be more worried about dehydration if he were vomiting and having diarrhea continously. Most cats aren't big drinkers. Keep a close eye and try what I mentioned. It should bring him along but if it doesn't then give your vet a call
thank you very much you have put my mind at rest.
You are welcome! Best of luck to you and Sawyer1!