When cats get diarrhea, it is a sign of something wrong. It is also very irritating to their insides (you often will see blood in the poop from the irritation).

Diarrhea can sometimes be hard to diagnose (I know, my Lucas has had diarrhea for 3 weeks and we cannot seem to find the cause, yet).

But it is something that you need to treat. You need to make sure they drink enough and that they don't lose their appetite. And we have had several vet visits and tests to try to determine what is going on.