In recent years, the ethnographic method has been found to be an adequate instrument for public health and health education interventions. Nevertheless, its use contradicts certain intervention models, defined here as monologic, such as mass media campaigns and "rational actor" philosophies. Some epistemological foundations for these models were analyzed, such as the one-dimensional analysis of health/disease/care processes, the one-way communication and their hierarchical nature. In its place, a dialogic model based on the ethnographic method and organized from the criteria of multidimensionality, two-way communication and symmetry is proposed. Ethnography enables the effectiveness of interventions to be improved by providing an empirical basis for project design and allowing for social participation in health.