The new One Health approach proposes to view the human-animal-ecosystems relations as a continuum. This systemic approach proves very valuable when examining the links between wooded green spaces in urban areas and the health of city dwellers (more than half of the world population). These links and their diversity and complexity are now beginning to be adequately documented by the scientific literature. Some benefits and risks for human health can now be better analysed enabling areas for useful action in the future to be identified.