Abstract
One Health can be defined as any added value in terms of health of humans and animals, financial savings or environmental services achievable by the cooperation of human and veterinary medicine when compared to the concepts of approaches of the 2 medicines working separately. This chapter examines the theoretical issues of One Health. One Health inevitably sheds light on the human-animal relationship and bond. It should reflect on the normative aspects (values) of the human-animal relationship with emphasis on improving animal protection and welfare in an inter-cultural context. One Health studies declare the perspective, i.e. the social, cultural and religious background, from which the human-animal relationship is seen. Improving animal welfare remains a permanent challenge to any effort and ethical aspiration of One Health. One Health engages with the public in a transdisciplinary way, considering all forms of academic and non-academic knowledge for practical problem solving at the animal-human interface. The strongest leverage of One Health can actually be observed when it is applied to practical societal problem solving. One Health approaches are embedded into ecohealth conceptual thinking, which are further expanded to 'Health in Social-Ecological Systems' addressing complex issues of human-environment systems.