Because your dog's bad breath could be a sign of serious dental problems, the experts at Purina developed Purina Dentalife ActivFresh, containing natural spirulina and honey, scientifically proven to fight bad breath at its source rather than just covering it up. ActivFresh is designed with the Dentalife shape, size, and chewy, porous texture that is scientifically proven to reduce tartar build-up. Don't hide bad breath, fight it at it's source with ActivFresh.