To relieve food allergies in dogs, the best and most accurate method of diagnosing a food allergy is to feed a hypoallergenic diet for 8 to 12 weeks as a food trial, called an elimination trial. Once the offending food substance has been identified, a diet that does not contain it is chosen. Today, there are several hypoallergenic diets available from your veterinarian that can be fed for the rest of your dog's life. There are three types of hypoallergenic diets: Veterinary hydrolyzed protein diet, in which the protein molecules are broken down to a size too small to be recognized by your dog’s immune system. Veterinary novel protein diet that does not contain any products that were present in your dog’s previous foods. Home-prepared novel protein diet that does not contain any ingredients that were present in your dog’s previous diets. Your veterinarian will prescribe the best option specific to your dog’s needs. Some dogs will require medication during severe episodes, but most pets can be successfully treated with a hypoallergenic diet.