Based on previous experience from two research projects on schistosomiasis in rural populations, this article focuses on the relations between scientific health knowledge and health-related common sense in farming communities. The article discusses factors that affect the meaning of participation by these communities in exogenous programs, as well as the dilemmas related to the appropriation, validity, and applicability of multiple and non- contextualized health information offered by such programs. The article discusses how the acritical aggregation of large amounts of information, a feature of globalization, deepens the feeling of uncertainty in rural communities and the trend to impute diseases to fatality. Meanwhile, the consumption of medical technologies is viewed as a symbol of progress and is highly valued by these groups. The discussion addresses the important role of health personnel in valuing local empirical knowledge, fostering the incorporation of useful technical knowledge without compromising the cultural heritage on which the identity and health of such groups are based.