Prescription Diet™ Canine z /d™ ultra Allergen-free has the following key benefits. Key Benefits · Helps minimise allergic reactions to food. The unique hydrolysed formula provides a safe solution to virtually any food allergy. · Chicken hydrolysate is the only animal protein source. · Helps nourish skin and coat as it is formulated with high levels of essential fatty acids. Please consult your vet for further information and guidance on what is best for your dog.