Abstract : Traditional knowledge of medicinal plants can be significantly beneficial for pharmaceutical research and development by documenting and reporting traditional knowledge. For this reason, we present our findings on ethnomedicinal plants from Setif city (Algeria). Information about ethnomedicinal plants was collected through questionnaires and semi-structured interviews from 300 informants. Quantitative analysis revealed that the city of Setif and its distinct regions are the main areas where medicinal herbs used to treat illnesses, with usage rates of 69% and 59%, respectively. Women were the primary users, comprising 95% of the respondents, particularly in the age group of 20 to 30, accounting for 61%. Polycystic Ovary Syndrome (PCOS) was the main disease treated, with a treatment rate of 86%. Additionally, Atriplex halimus L. was the dominant plant used by 93% of respondents, from a general use rate of 49% for medicinal plants used for therapeutic purposes by 71%. Leaves were the most commonly used plant parts (60%), followed by whole plants (35%), and the preferred method of preparation was infusion (56%), it was used for a period of one to three months. No cases of poisoning were recorded. In summary, by combining indigenous knowledge with scientific validation, our study highlights that A. halimus is a curative treatment, underscoring its traditional medicinal value. This study provides a promising avenue for future research on plant-derived remedies, particularly against PCOS.