H-1 and O-17 NMR spectroscopy has been used to study the fragmental composition of extracts and changes in the structure of water in the gasoline-water system, The contribution of the interaction between oxygen and hydrogen nuclei of water was separated from the contribution of the reaction of water with the organic components of gasolines by using {H-1}-O-17 double heteronuclear resonance. It was established that the reaction of gasolines with water is determined by concurrent mechanisms of breakdown of the structure of the water through the formation of PhAlk-H+ structures and strengthening of the structure of the water through the reaction of aliphatic hydrocarbons with water molecules.