ETHNOPHARMACOLOGICAL RELEVANCEThe ethnobotanical survey was carried out in the Bac Huong Hoa Nature Reserve (BHHNR), Vietnam. The Van Kieu ethnic group, the inhabitant of Nature Reserve, is rich in knowledge about the medicinal plants found in the Nature Reserve. However, their knowledge is less documented. AIM OF THE STUDYThe present study was conducted to document the use of medicinal plants, plant parts used, mode of preparation and delivery by the ethnic group of Van Kieu. The study also aimed at comparing the information generated by this study with the previously published Dictionary of Vietnam Medicinal plants (DVM). MATERIALS AND METHODSThe information was collected through semi-structured and unstructured interviews. The interviews were conducted from April 2016 to March 2017. The number of informants involved in the survey was 93 belonging to age group of 20-81. Species Use-Reports (UR) were analyzed to determine the plant importance in the local and the Informant Consensus Factor (FIC). Local plant uses were listed and compared with the previously published data from Vietnam. RESULTSComprehensively 355 Use-Reports were documented in this study. A total of 111 medicinal plant species belonging to 102 genera and 46 families were reported. Out of 46 families, Euphorbiaceae (10 species), Compositae and Leguminosae (9 species each), Apocynaceae (7 species), Rutaceae and Rubiaceae (5 species each) were the dominant families. Leaves were the most frequently used plant part (43.1%) in the preparation of medicines. The most frequent preparation method was decoction (49%) while the oral route of administration (51%) was the most commonly mentioned mode of administration. Artocarpus heterophyllus Lam., Chromolaena odorata (L.) R.M.King & H.Rob., Blumea balsamifera (L.) DC., Psidium guajava L. and Catunaregam spinosa (Thunb.) Tirveng. were shown to be the most useful plants as indicated by their relatively high UR. Eight medicinal plants (7.21%) used by Van Kieu ethnic people have not been previously reported in DVM. CONCLUSIONThe Van Kieu ethnic group holds valuable knowledge about uses of medicinal plant resources which is inherited through generations however this knowledge was not documented. The study highlights the need for documenting and publicizing the traditional medicinal knowledge which will provide basic data for further research and conservation.