Hill's Prescription Diet y/d Feline is a scientific breakthrough - the first and only clinically proven pet food to help support your cat's thyroid health! NEW Prescription Diet y/d has restricted levels of dietary iodine to help support thyroid function. The thyroid gland produces hormones that have an impact on a variety of metabolic functions from appetite regulation to heart rate gut function to behavioural characteristics. A cat with a healthy thyroid has a body that's kept in balance with the end result that your cat feels great. As easy as feeding Prescription Diet y/d is effective and safe and its great taste will ensure your cat will love it! But that's not all - there are other additional health benefits to your cat: Supports kidney health with controlled phosphorus and low sodium. Helps maintain bladder health with controlled mineral levels. Supports healthy heart function with high levels of L-carnitine. Promotes healthy skin and a luxurious hair coat with high levels of Omega-3 and-6 fatty acids. *Re-checks are at the discretion of your recommending vet; it is recommended that cats with compromised kidney function should be seen more frequently. Concurrent use of the medications Felimazole or Vidalta when feeding Hill's Prescription Diet y/d is not recommended and therefore initial vet recommendation is required.