Abstract: A method of obtaining a free disperse system in liquid which produces a controlled hydrodynamic cavitation by regulation of constriction ratio, volumetric flow rate, and degree of cavitation parameters. Selection of the parameters with regard to the properties of components of the fluid make it possible to effectively treat the components having a variety of physio-chemical characteristics. The invention further relates to the construction of a cavitation device wherein the geometry of a flow-constricting baffle body effectively increases the degree of cavitation to substantially improve the quality of an obtained free disperse system.