An ethnobotanical study was carried out in the Portuguese Serra do Açor, situated in the center region of Portugal amid the Serra da Estrela and the Serra da Lousa mountains, between January and June 2003. This work was based on 60 interviews with 30 inhabitants from 12 villages of this mountain chain who were acquainted with the uses of its vegetation. Information about 14 taxa with toxic, ichthyotoxic, insect-repellent, and bee-attractant uses was compiled, including their vernacular names, toxic principles, parts used, and preparations.