This study combined anthropological and epidemiological approaches to assess the effectiveness of community mobilization for health education, developed as part of the Brazilian program for the control of schistosomiasis. The study was carried out in two villages in the state of Minas Gerais, SE Brazil, exposed to the same established schistosomiaisis control strategies. Residents of one village were also exposed to the community mobilization for health education (study area) while those from the other community were not exposed to this program (control area). Schistosoma mansoni prevalence rates for the study and control villages were compared over time. A population-based survey was carried out in the two villages to obtain information on socio-demographic factors, water contact patterns and knowledge of S. mansoni transmission. Intensive ethnographic interviews with key informants in each locality were employed to determine the knowledge, attitudes and practices of the communities regarding schistosomiasis. Ethnographic data were analysed using the model of systems of signs, meanings and actions. Differences were observed in prevalence trends between the study and control areas but they could not be explained by the existence of the community mobilization program in the former. It was also found that educational actions carried out by the Brazilian Ministry of Health transmitted information on schistosomiasis but were ineffective in transforming the information received into preventive behaviour related to water contact. With regard to disease, the population studied tended to distinguish minor symptoms, which they associated with water contact, from major symptoms, which they attributed to lack of medical treatment. This distinction mediated perceptions of the severity of "xistose" and reduced the importance of avoiding contact with potentially infested waters. The perception of protection conferred by treatment observed in the present study might also apply to other communities where access to treatment is readily available and free. The extent to which this perception exists in endemic areas needs to be determined so that apparent contradictions of this type can be addressed in future educational programs.