If your cat shows one these following signs, it means that the cat had suffered from cat food poisoning. First, it gets vomiting or diarrhea. Second, its behavior becomes lethargic. Third, it looks weak and often gets staggered. Fourth, it develops too much salivation. However, since these signs can also indicates the other types of cat illness, it is better to take it to the vet as soon as possible to make sure that it only gets the low risk poisoning and not the serious symptoms. If it is safe and is suggested by the vet, you can treat the cat by your own.