For the Nutritional Management of Dogs with Food Allergy and Intolerance. Food allergy and intolerance are potentially serious problems that can result in sensitive or irritated skin, coat and ear conditions or even digestive problems. Dogs that have food allergy or intolerance, also called adverse reactions to food, typically are having an abnormal response to the protein in the food. Only Prescription Diet z/d ULTRA Allergen Free Canine canned dog food is formulated with Hill's Hydrolyzed Protein System, a process that breaks down intact animal proteins and significantly reduces the possibility of an adverse reaction to food. Reactions usually occur as a result of beef, dairy products and wheat. z/d ULTRA Allergen Free Canine canned contains none of these allergens. The nutritional formulation of Prescription Diet z/d ULTRA Allergen Free canned may also be useful for pets with a variety of conditions.