The objective of this work was to investigate, rescue and document popular knowledge about the use of medicinal plants in the promotion of animal health in the Alto Médio Gurguéia microregion, Piauí. We interviewed people with experience at animal husbandry, and with knowledge about the use of medicinal plants, using non-random sampling. For this purpose, visits were made to rural properties and to support agencies for rural producers (ADAPI and EMATER). There were 61 interviews were conducted between producers and professionals in the agrarian sciences, regardless of sex or age. For the interviews, semi-structured forms with open and closed questions were used. During field research 43 species of plants used in the treatment of animal diseases or conditions were cited. Only at six most cited are described in the table, Aloe Vera L., Drimys brasiliensis, Poincianella pyramidalis (Tul.), Chenopodium ambrosioides L., Gossypium hirsutum, Caryocar coriaceum Wittm, Hancornia speciosa Gomez, Guapira graciliflora, Mauritia flexuosa, detailing the taxonomy, therapeutic indications, the parts used, the methods of preparation and the treated animals. The species described were the most cited not by coincidence, are plants that stand out in several ethnobotanical researches and demonstrate a wide medicinal potentiality, even though they have scarce scientific evidence of their biological activities.