had a cat years ago who couldnt keep his food down, he was not entire but i had a queen who was and attracted toms, so we and the vets put it down to stress, he continued to vomit after feeds so the vet treated him for stomach ulcers, still it continued by now he was looking a bit thin, so they treated him for fur balls, still he continued to vomit so as a last resort they gave him a course of anti-biotics and hey pressto....... was back to his old self
