The aromatic xenobiotics 2,6-dimethylphenol, 4-chlorophenol and naphthalene were removed using hydroponic cultures of Carex gracilis and Juncus effusus and using sand-bed reactors planted with Carex gracilis and Juncus effusus, respectively, under batch and flow-through conditions. Concentrations of 20 mg/l organic pollutant in the case of 4-chlorophenol. about 30 mg/l naphthalene and 50 mg/l 2,6 -dimethylphenol were efficiently eliminated over periods of up to six months. Plant cultures were found to achieve a better removal rate than plant-less systems. In the systems investigated, organic xenobiotics are thought to be mainly degraded by bacteria in the rhizosphere. The plants were not observed to suffer any damage when exposed to the above-mentioned pollutant concentrations. Indeed, plants responded to 2,6-dimethylphenol with better growth, implying that the plants benefited from the xenobiotic. However, whereas Carex gracilis plants exposed to more than 10 mg/l 4-chlorophenol initially died off, after a few weeks' of exposure up to 10 mg/l, they tolerated up to 30 mg/l 4-chlorophenol.