First ethnobotanical study relating to usage of medicinal plants in province of Ain Defla region, South-West of Algeria

The study was performed through 2019–2021 in Ain Defla province (South-west of Algeria) including 10 municipalities. Ain Defla has a wide diversity of plants used by their inhabitants for therapeutic aims. The data were collected and recorded using a feedback form, from a pre-established population, targeting on informants demographics, medicinal plants and parts used, method of treatment, and diseases treated. The collected information were analysed in terms of species use value, fidelity level and informant consensus factor. 180 people were interviewed; gender distributions (40%) ladies and 60% were men. The study recounted 65 medicinal plants belonging to 33 distinct families, of which the Lamiaceae are the most commonly used. The most used parts of plants are leaves. The most common mode for therapeutic preparations was infusion. The most frequently plant used was T. munbyanus with 1.07 following by Allium cepa was with 0.69 of use value, respectively. The highest fidelity level was recorded for Petroselinum crispum with 100% for treatments of cardiovascular diseases, follow by Inula viscosa with 86% for gastrointestinal diseases. The informant consensus factor varies from 0.75 to 0.96 and gastrointestinal diseases with 0.96 represented the highest informant consensus factor.