So a few weeks ago, my first cat started to vomit everywhere. We took her to the vet and they said her bowels didn't seem to be moving. They gave me a pill to stop her vomiting and some probiotics. She's been passing and stopped vomiting for about two weeks. Well today she threw up again. I've been giving her lactulose and canned pumpkin in her food and she has been passing still. Well now my other cat, after having some food of the others with probiotics in it, has been having watery diarrhea for the passed 3 days. I am at a loss of what to do and what could be causing this...their food hasn't changed. All I can think of that has is their litter, which I started using arm & hammer brand. Any help or advice is much appreciated!