Hi, I have two cats and one is always being constantly sick after eating her food. I have taken her to the vets a couple of times to get her checked out and nothing appears to be wrong, the vet said that some cats just do this. He did xray her to make sure that she had no blockage anywhere and also checked her throat for soreness/infection as a result of constantly bringing up her food, but she was fine. My advice would be not to worry too much, but take him to the vet for a checkup anyway.