Trichoderma spp. probably have a role in remediation of polluted soils and waters. Highly rhizosphere competent strains persist on roots for an extended period of time (at least months) and continuously interact with the plants. They can increase general plant and root growth and increase uptake of a variety of materials. This makes the Trichoderma-plant interaction highly attractive for use in phytoextraction technologies. Moreover, Trichoderma spp. are resistant to a wide range of toxic compounds and can degrade some of these. One highly attractive target for remediation are soils that are polluted with cyanide and metallocyanides. Shrub willows (genus Salix) have been shown to take up and degrade these compounds by unknown mechanisms. Thus, they remove these compounds from soil but there are no cyanide residues in the plants. Similarly, Trichoderma spp. degrade free cyanide via production of extracellular enzymes and take up and then degrade metallocyanides such as Prussian blue. The willow-Trichoderma system therefore provides a plant-microbe system for degradation of these toxic compounds. The fungi also can be used directly in remediation strategies; for example,they degrade polyphenols such as those found in large quantities in waste water from production of olive oil. Thus, the abilities of the fungi to interact and enhance plant growth, their ability to grow in the presence of toxicants and their enzymatic abilities to degrade polluting substances provide a number of opportunities for either plant-microbe or pure fungal systems to remove pollutants from lands and waters.