Caatinga forest resources have been the subject of intense utilization to overcome human needs such as food, clothing, leisure, housing and population health. Ethnobotany is a science of great interest for research in the caatinga, because this branch of knowledge is concerned with the analysis of information that man has on the use of plants. Among the lines of the ethnobotanical studies the medicinal plants are highlighted, and they are used in the manufacture of home medicine, especially by traditional communities. This study conducted ethnobotanical surveys on the use of medicinal plants in the municipalities of Picuí, Nova Palmeira and Frei Martinho which belong to the Microregion of Seridó Oriental da Paraiba, Brazilian Northeast. In each town an urban and rural area was analysed. The ethnobotanical information was obtained through semi-structured questionnaires containing socioeconomic characteristics of the respondents, botanical characteristics of plants and their therapeutic uses. We selected an adult which is the responsible for the residence "householder" for the interview and used the technique of "snowball". Among the participants of the survey, the majority was a female, aged between 25-75 years and had low education. The most referred plant families were Fabaceae, Euphorbiaceae and Asteraceae. The species most frequently cited were Amburana cearensis (Allemão) A.C. Sm. (46), Chenopodium ambrosioides L. (39) and Plectranthus amboinicus (Lour.) Spreng. (32). The predominant habit was herbaceous, followed by woody; the parts of the plant which were most used were the leaves and bark of the stem; the main modes of preparation of medicines were showers and oral. The plant with the highest CUPc was Anacardium occidentale L. (66,7%) and with the greatest Fri was Amburana cearensis (Allemão) A.C. Sm. (27,3%).
