The present study was carried out in the Environmental Protection Area of Serra da Ibiapaba, in Cocal Municipality, Piauí. The study aimed to perform a survey of the plants used by the community, including used parts, recommended use, forms of use and administration of these plants. A total of 80 interviews were done with 100% of denizens with noteworthy knowledge who lived in that municipality and used and/or commercialized plants of medicinal use. To define the sample the snowball method was adopted. In tours guided by members of the community, the cited ethnospecies were collected. After this stage, the species were identified in the laboratory and the Informant Consensus Factor (ICF) was calculated for each disease category. The material was incorporated in the collection of Herbarium Graziela Barroso (TEPB/UFPI). A total of 76 species were identified, distributed into 61 genera and 36 families. Leguminosae was the major family with 22 species (28.9%), followed by Euphorbiaceae with 6 (7.8%) and Solanaceae with 4 (5.2%). Croton L. and Hymenaea L. were the most important genera, comprising 8 (10.5%) of the total species. The species most commonly recommended for medicinal use were Ximenia americana with 14 (5.9%), Tabebuia impetiginosa with 9 (3.9%) and Anacardium occidentale with 7 (2.9%). The age of 80.5% of the interviewees was over 50 years and they had been living in the municipality for more than 20 years, while 70% had only incomplete elementary education and 20% were illiterate. There was greater consensus among the informants for treatment of respiratory diseases (0.66) and problems of the digestive system (0.65). The most common recommendation of use, 81 (34.17%), reported for 28 (36.8%) of the species, aimed to cure problems of the respiratory system, such as asthma, bronchitis, influenza, inflammation of the throat, pneumonia, and sinusitis. In the preparation of medicines, the parts most commonly used were the bark (30.5%), the leaves (29.4%) and the roots (12.6%). The most common preparations were tea, balm and lickers, administered orally. The results indicated the importance of the bioactive potential of "carrasco" vegetation.
useful plants; ethnobotany; ethnomedicine; semiarid region
