Before you give anything recommended on here please consult your vet. There are a lot of great products but you need to be sure dosage wise that you are administering the correct amount. Purina Fortiflora is sold across the counter at vet offices and are extremely safe and affective. It's an item that flies off the shelf. All other holistic supplements can be tricky and actually make matters worse if the wrong amount is given but they can create amazing results if handled responsibly.