Cat MedicineKeep a supply of cat diarrhea medicine handy for your pet's cat health. Because your cat can get sick sometimes just as you do, keep some commonly needed medications in your personal first aid kit for pets. This first aid kit can include cat diarrhea cat medications for immediate use. However, if your cat's sickness is pretty serious, it is still best to head for the nearest veterinarian's clinic. When looking for anti-diarrhea medicines for cats, opt for those that are easy to administer because of their pleasant taste.