In order to understand and take action in complex health and environmental issues, we intend to analyse the conditions that are needed for those at risk to participate in research and intervention projects. In this study, we describe and discuss an action research experience carried out with an indigenous community in the Brazilian Amazon that suffers from serious sanitary problems, where cultural aspects in the relationship with the environment and health are particularly relevant. Different types of tools were deployed and combined and were subsequently classified according to their dialectic efficacy and ability to both conduct and steer the research and encourage the participation of social actors within a process of feedback. Even tools that were considered to be non-dialectic proved to be important sources of feedback. We present a research flow as a model of analysis and a framework for implementing action research, in which challenges to the participation of social actors are classified according to their priority through a critical review of the methodology developed. These challenges are social mobilization, co-operation, appropriation and a proactive stance. We conclude that a cyclic combination of dialectic and non-dialectic tools can increase participation, which though difficult to achieve is nevertheless necessary. During the development of this process, social mobilization is a prerequisite, whereas a proactive stance, the highest level of participation, requires continuous effort and the successive deployment of a variety of tools. [ABSTRACT FROM PUBLISHER]