Medicinal plants and their traditional uses in the highland region of Bordj Bou Arreridj (Northeast Algeria)

[Display omitted] •Ethnobotanical surveys in the Bordj Bou Arreridj region during a two-year period (2014–2016).•Surveys concerned the profile of the interviewed herbalists, the plants and their uses.•Data were analyzed using the Use-Value of species and the Informant Consensus Factor.•New uses and new medicinal plants in Algeria.•Importance of taxonomy and chorology in ethnobotany. In the highlands of Bordj Bou Arreridj in Northeast Algeria, traditional knowledge about medicinal plants is still put to use, but has been poorly explored by researchers. In view of its natural and cultural richness and the socio-economic context, this area is an ideal location for the study of aromatic and medicinal plants and their traditional uses. The aim of this ethnobotanical study was to shed light on how medicinal plants are used in traditional phytotherapy in the region of Bordj Bou Arreridj. Over a two-year period (2014–2016), herbalists practicing phytotherapy in the region were surveyed, and asked to provide information about themselves and the plants they used (vernacular name, mode of preparation, parts used and toxicity). The data was analyzed in terms of the Use-Value of species (UV), Medicinal Informant Agreement Ratios (Med. IARs), Fidelity Level (FL) and the Informant Consensus Factor (ICF). Among the 51 herbalists interviewed, men dominated the practice of traditional phytotherapy. The majority of these herbalists, whose ages varied between 46 and 65, were illiterate. During the survey, 83 species of medicinal plants were identified. They belonged to 66 genera and 37 botanical families, among which Lamiaceae were the most used. The herbalists most commonly used plant leaves, and for the most part, preferred to prepare the remedy in the form of infusions. Origanum vulgare subsp. glandulosum (Desf.) Ietsw., Rosmarinus eriocalyx Jord.& Fourr. and Allium cepa L. were the plants with the most important UV. Thirty-eight species had maximum values for the Med IARs index and digestive diseases were those with the highest ICF value. Interviewees indicated 10 taxa possessing toxicity but did not indicate the toxicity limits of each plant. Taxonomic analysis allowed the authors to recognize several taxa having changed systematic positions and/or nomenclature. The chorological analysis led the authors to distinguish 6 endemic taxa and 13 taxa that were not native to the country. The importance of this study lies in the originality of the information obtained, which mus