Hill's nutritionists and veterinarians developed Prescription Diet® l/d®, clinical nutrition especially formulated to support your dog's liver health. In fact, l/d is formulated to help protect vital liver function. It helps reduce liver workload allowing liver tissue to regenerate with moderate levels of high-quality protein. It is formulated with appropriate levels of zinc and low copper. It is designed with clinically proven antioxidants for a highly palatable formula your dog is sure to love.