The xenobiotics are chemical substances not found in a biological system or organism. The presence of these substances in the soil negatively affects the ecosystems and there is a need for clean up techniques of these areas. The phytoremediation is a methodology that applies some plant species and the microorganisms associated to them in order to degrade, contain or quelate pollutants in contaminated places, and it is becoming very popular due to its low costs, to its possibility of in situ application, and to the little disturbance that it causes in the area. PAHs are the most ubiquos hydrophobic organic contaminants on the Earth. Although they occur naturally, anthropogenic processes are considered to be their main source in the environment. Several plants, especially Leguminosae, have been identified by their potential to facilitate, by different mechanisms, the phytoremediation of degraded areas. Plants generally metabolize xenobiotic pollutants by a sequence of three steps: activation/conversion of lipophylic xenobiotic components, conjugation of the metabolized xenobiotics, and compartmentalization of the formed conjugate. Some species have already been identified as able to develop in degraded areas and others have been applied successfully to the study and recovery of these areas, although there is still a great lack of information on the subject, particularly about Brazil’s native species.