Hill's nutritionists & veterinarians developed Hill's Prescription Diet z/d clinical nutrition especially formulated to support your cat's skin and food sensitivities or intolerances. In fact, z/d is clinically proven nutrition to help avoid adverse reactions to food. Hill's Prescription Diet Z/D Feline contains hydrolysed proteins and enriched with essential omega fatty acids. Hill's Prescription Diet Z/D Feline provides digestible proteins and single carbohydrates source so that your cat shows minimal adverse reactions. With increased antioxidants and Omega 3 and 6 fatty acids to maintain a healthy immune system, digestion & stool quality, and a healthy skin barrier functionality. Available in 2 sizes, Prescription diets should only be used with the professional advice of your Veterinarian.