How To Know If Your Cat Is Sick. To know if your cat is sick, watch for symptoms like frequent diarrhea and vomiting, which could be a sign that something is wrong. There are some cases where changes in the cat's home life can cause the cat to stop using the litter box, but this is a behavior that should always be investigated as a health problem.
I didn’t know what it was at the time but looking back it seemed a little bit as if it was. 5 alarming sick cat symptoms. It may be one of the signs your cat is dying.
Be aware of what’s normal for your cat.
The cat who learned to associate the box with discomfort, for example, or the cat who learned it’s just as easy to go on the rug will need retraining after the medical problem has been resolved. It may be difficult to know if subtle changes in your cat indicate a health problem. These can be signs your cat is sick: It may not be very specific, but you will notice some subtle changes to begin with.