Background This study aimed to contribute to the valuation of medicinal plants used in the treatment of diseases affecting the populations of the district of Yagoua. Methods Ethnobotanical data was collected in 10 villages from June to August 2020 in Yagoua. A total of 300 informants (193 men and 107 women) were interviewed through semi-structured interviews, key informant interviews and guided field visits. All informants were local residents between the ages of 15 and 60, and key information holders were selected based on recommendations. The frequency of citation (FC) made it possible to appreciate the local phytotherapeutic importance of each species, the Degree of Fidelity (DF), identified the species most used in the treatment of a particular disease and the informant consensus factor (ICF) was used to determine the homogeneity of knowledge in the use of medicinal species. Results 98 plant species were identified belonging to 85 genera and 47 families. The Caesalpiniaceae families dominate (9 species). 10 species have a high frequency of citation. A total of 31 diseases were recorded, 8 of which had a high frequency of occurrence. It was found that men have more knowledge about plants (64.33%); the age group 26–36 is interested in the use of plants. 150 recipes were identified, of which 78.67% were monospecific. 49.44% of the species used by the population are collected in the bush, 5 morphological types represented 68.36% of woody plants and 31.64% of herbaceous plants, sarcochores are the most represented diaspore types with 51.02%. Leaves and barks are the organs most frequently used for the preparation of recipes; decoction is the most commonly used method of preparation and the oral route is the most commonly used way of administering medicines. More than half of the species recorded have a level of fidelity equal to 100% and the informant consensus factor shows high values. Conclusion The study area is rich in important plant resources for which the populations must be aware and must also take into account their vulnerability by advocating reforestation, domestication and sustainable use.