The development of civilization is associated with introducing of new and very complex chemical products. A very promising method to eliminate contaminants is thermohydrolysis in supercritical water, using the properties of water after exceeding its critical point. The process of thermohydrolysis of stilbene derivatives was investigated in the study. The degree of toxicity of the starting compounds and mixture formed after thermohydrolysis to aquatic organisms (crustaceans and fish) was determined. The degree of biodegradability of the analyzed acids and products of their decomposition was also examined. The results of biological tests indicate that as a result of the degradation process in supercritical water at a temperature of 600 degrees C and pressure 25.0 MFa, mixtures of products with toxicity to organisms of the aquatic biocenosis very different from that of the initial compounds are obtained. The mixtures are characterized by low toxicity and a very high degree of biological decomposition.