This work is based in the investigation about the persistence of the use of medicinal plants in the communities inhabiting the wetlands within Iberá Natural Reserve. From the participant observation and semi-structured interviews, together with the collection of reference plants, the use of 90 medicinal plants to treat 171 ailments, distributed in 12 body systems was recorded. In addition, the informant consensus factor was also calculated and a correspondence analysis was made. It was concluded that the use and knowledge associated to medicinal plants remains active, depending mostly of the native species. For this reason, the maintenance and access to the native flora by ancestral communities is suggested, to conserve the biological and cultural diversity of the Iberá Natural Reserve.