Planetary health is not only a new field of research and practice; it is also a moral ideal. What are the implications for medicine and health care? In this article, we argue that within this ideal, health of humans, animals and also nature are worthy of protection for their own sake. These values can reinforce each other, but they may also conflict. We formulate a general framework that provides some direction for ethical reflection. Next we discuss implications of the ideal of planetary health for zoonotic disease outbreaks, for environmental sustainability of health care, and for global health and solidarity in the face of climate change. Planetary health demands much from health care, and this will also further exacerbate existing policy dilemmas.@en