Abstract: A method of obtaining a free disperse system and a device for producing the cavitation effect is provided in which the passage of a hydrodynamic flow through a channel internally accommodating a baffle body providing a local contraction of the flow in at least two sections and forming a cavitation field downstream of the body. The ratio of velocity of the flow at each of the sections to the velocity of a free disperse system at the outlet of the channel is maintained equal to 2.1 and the degree of cavitation is maintained at a level equal to at least 0.5. A cavitation device comprises the baffle body including at least two elements providing generation of their own cavitation fields different in the degree of cavitation.