This paper reports on the challenges that were experienced as I engaged in an action research project in which I designed and enacted a cross-cultural unit of work entitled "Maintaining Health". George has advocated the use of traditional knowledge as a strategy for increasing the relevance of science curricula within the Trinidad and Tobago context. My intention therefore was to improve my practice and to facilitate students' access to conventional science concepts by having them build bridges between their traditional knowledge about health-related matters and conventional science concepts. This type of investigation was an innovation in science teaching in Trinidad and Tobago. In my role as teacher-as-researcher at a single-sex (female) urban secondary school--Parkview Secondary--I engaged in the first action research cycle--plan, act and observe, reflect--with a group of form 2 students (12-15 years). My reflections on the planning phase were recorded in a journal, and the data from the classroom enactment were audio-taped and transcribed. These data were analyzed qualitatively into themes by use of grounded theory methodology, which is appropriate when little is known about the subject being investigated. Among the challenges that emerged during the first action research cycle were "resistance and doubt", "level of teacher control", and "communicative competence: the language of bridge-building". Based on these findings, a second action research cycle was enacted with another group of form 2 students who attended a rural co-educational school located in Seablast. The results of this second enactment revealed evidence of the three themes and also an overall improvement in my use of the language of bridge-building, suggesting that change occurs over time and is facilitated by the process of reflection on evidence gathered systematically. Action research is therefore recommended as a strategy for teacher development. Through the process of reflection teachers can begin firstly to understand their practice; secondly, to understand the change process as they seek to improve their practice, and, thirdly, to acquire the skills that are congruent with the new relationships among teacher, student, subject matter, and context. (Contains 1 table.