Medicinal plants are being used in different contexts as a therapeutic resource. Some times the scientific knowledge is in conflict whit popular knowledge, but in another occasions we found a dialogue between them. In this study, where analyzed the talks of participants in three events about medicinal plants in State of Paraná (Brazil) in the year of 1999. We observed that in those events, although controversies/conflicts exist between representatives of popular and scientific knowledge, a dialogue is happening, trying to reach a safe and efficient medicine to population.