Royal Canin Veterinary Diet Canine Hydrolyzed Protein HP Dry Dog Food does not contain any artificial colors or flavors. However, it contains some artificial preservatives, such as BHA and BHT. BHA and BHT are commonly used as preservatives in pet foods to help maintain the quality and freshness of the prescription food. They are generally recognized as safe by the U.S. Food and Drug Administration (FDA) and are usually used in many pet food products.