Abstract. With the development of synthetic chemistry, combinatorial chemistry and pharmaceutical chemistry, millions of new compounds are being synthesized. Classical chemical substance evaluation needs a lot of time and is expensive, and the speed of analyzing the toxicity of compounds is less than the speed of discovery of new compounds. Quantitative structure-activity relationships (QSARs) have been efficiently used for the study of toxicity mechanism of various compounds. All organic chemicals have the potential to cause narcosis. Their ability to do so is mainly governed by their concentration and their ability to cause more serious toxic effects, which would mask any narcotic effect the chemical may cause. Esters possess physicochemical properties of nonpolar narcotics such as nonreactivity and low water solubility associated with low polarity. The aim of this study was to research and compare the acute toxicity of benzoates for different species (aquatic and terrestrial).