Yes, Hill's Prescription Diet m/d GlucoSupport with Liver Flavor Canned Cat Food needs a prescription. Like a lot of veterinary pet food, the GlucoSupport by Hill’s requires authorization from a licensed vet. Veterinary diets are made using special ingredients in certain amounts. They have a very specific nutritional formula that is mostly used to address certain medical conditions. And since these diets deal with medical issues, you must first consult a vet before giving the food to your pet. The GlucoSupport is a prescription diet that helps keep your cat’s weight and glucose levels in check. And to do so, it must be given to them in proper amounts, which is why you have to talk and ask your veterinarian for permission first before you give the food to your cat.