Vegetation is able to remove, contain or render harmles environmental organic contaminants. Recently this ability of plants has been used for in situ treatment of contaminated soils and sediments and this technology - phytoremediation - has already been shown to be effective in a number of full-scale and pilot studies This paper provides an overview of the experiences of the practical use of phytoremediation in decontamination of organic pollutants, summarizes the advantages and disadvantages of this technique in contrast with other technologies. Enzymes taking part in transformation reactions are described and the mechanism used by plants for the transformation and degradation of organic pollutants are discussed. The use of plant cells cultivated in vitro as model systems for studying the metabolism of exogeneously applied pollutants is also shown.