Introduction: The present study falls within the framework of valorization of medical plants and traditional knowledge's in the Northeastern part of Dahra Mountain, Algeria. Methods: An ethnobotanical survey was conducted between 2016 and 2018 in order to study the traditional and therapeutic use of medical plants amongst the local population. Data collected was analyzed using quantitative indices such as the fidelity level (FL) and Informant Consensus Factor (FIC).
Results:The results revealed 70 medicinal species belonging to 38 botanical families, among which, five families were the most commonly used by the local population, especially the families Lamiaceae and Asteraceae. In term of species, the highest frequencies of medicinal use were shown respectively by Tetraclinis articulata (Vahl) Mast. (6.49%), Pistacia lentiscus L. (6.11%), Myrtus communis L. (5.34%) and Thymus vulgaris L. (4.96%). Among the various parts of the plant, leaves were the most used part and decoction was the most frequent form of use. Finally, the gastro-intestinal system disorders were the most treated diseases with a percentage of 28.24%. Conclusion: This first ethnobotanical study conducted in the region of Bissa revealed a very rich local knowledge in term of traditional herbal medicine; this fact was reflected by the high diversity of species used in the treatment of several diseases. In light of this, it is therefore very important to subject some of the major species to further phytochemical and pharmacological studies in order to validate their traditional use and to probably discover new bioactive molecules. This paper documented the results of ethnobotanical study carried out in the northeastern Dahra Mountains, Algeria. A total of 70 species belonging to 38 families. Lamiaceae and Asteraceae were the most used plant family by the local population. Leaves were the most used part, the majority of remedies were prepared as a decoction and gastro-intestinal system disorders were the most treated diseases. This first ethnobotanical study conducted in the region of Bissa revealed a very rich local knowledge in term of traditional herbal medicine.