It is not yet clear whether or not vitamins and supplements should be administered in dogs—opinions among veterinarians vary widely. While some think that vitamins and supplements are necessary and can improve the health of a dog, others believe that they are unnecessary and may harm the dog. According to the U.S. Food and Drug Administration (FDA), dogs receive a complete and balanced diet from the commercially processed dog food alone. Pet owners who give their dogs homemade diets may incorporate extra vitamins and supplements.