Algerian arid zone presents a rich diversity of medicinal plants and ethnoecological knowledge. Ethnobotanical study of medicinal plants was carried out in the Wilaya of el bayadh (Laguermi Zone). The purpose of this study is to compile a catalog of medicinal plants, to gather all the information concerning the therapeutic uses practiced by the local population in the region studied. A survey was carried out among the elderly in homes, and the annex of the National Biological Resource Development Center of Laguermi, one hundred (100) questionnaire sheets for two months. The results helped to identify medicinal plants divided into twenty-eight 28 families among which the Lamiaceae and the Asteraceae are the most for the majority of remedies. The results are a valuable source of information for both the study area and the national medicinal flora; it could be a database for further research in phytochemistry and pharmacology fields to search for new natural substances.