The increasing availability of data and improved analytical techniques now enable better understanding of where environmental conditions and human health are tightly linked, and where investing in nature can deliver net benefits for people—especially with respect to the most vulnerable populations in developing countries. These advances bring more opportunities for interventions that can advance multiple SDGs at once. We have harmonised a suite of global datasets to explore the essential nexus of forests, poverty, and human health, an overlap of SDG numbers 1, 2, 3, 6, and 15. Our study combined demographic and health surveys for 297 112 children in 35 developing countries with data describing the local environmental conditions for each child (appendix).4 This allowed us to estimate the effect forests might have in supporting human health, while controlling for the influence of important socio-economic differences.4 We extended this work to look at how forests affect three childhood health concerns of global significance for the world's poorest people: stunting, anaemia, and diarrhoeal disease.