In this interview, Dr. Oz speaks with author of “Angel on a Leash,” David Frei, about the amazing healing moments he’s witnessed his therapy dogs perform. Animal-assisted therapy uses dogs or other animals to help people recover from or better cope with health problems, such as heart disease, cancer and mental health disorders. David explains how to tap into the healing powers of your pet, and why we’re only just scratching the surface of this growing field of medicine.