[Challenges for knowledge generation in environmental health: an ecosystemic approach].

This article examines opportunities and limitations regarding knowledge generation in the field of environmental health. The contention is that understanding the complexity of factors that determine the health of humans and ecosystems requires a redefinition of the traditional distribution of roles and responsibilities in scientific research. These research practices involve inter and transdisciplinary approaches and the application of an ecosystemic approach (ecohealth). Challenges and opportunities associated to the application of inter and transdisciplinarity in environmental health problems are discussed and illustrated by two case studies that use an ecohealth approach: a project on the contamination and exposure to mercury in the Brazilian Amazon, and another on the urban transmission of echinococcosis in Nepal. In the conclusion, the potential benefits of using an ecohealth approach in overcoming the limitations of unidisciplinary practices and in taking advantage of local knowledge and participation is stressed.