The purpose of the paper is to demonstrate the usefulness of techniques of molecular similarity as an alternative method for estimation of both acute toxicity of chemicals and their partition coefficients. The technique of atom pairs was chosen. A series of aliphatic alcohols was treated. Acute toxicity was determined by the express laboratory method as the EC50 (inhibition of movement of the worms Tubifex tubifex). Partition coefficients were determined between oil and gas. The calculated results were sufficiently close to both experimental results and the estimates calculated by a technique of QSAR analysis.