Nowadays valuable pharmaceutical and terapeutical properties of preparates prepared from vegetal raw materials attract a special attention. There is an obvious necessity to investigate the physicochemical properties of biologically active compounds containing in medicinal plants, to develop extraction technologies and methods to control the end product quality. Usually, biologically active substances (BAS) can be extracted from raw materials using various solvents. The following factors should be taken into account while using this method of extraction: the nature of the solvent, the degree of dispergation of the raw material, the proportion between the raw material and the solvent, the process duration and temperature, as well as the influence of agitation and the method of separation of the end product.     Application of ultrasound-assisted extraction (UAE) for elimination of biologically active substances from vegetal raw materials is one of the most important techniques. It is versatile and can be used both in laboratory and commercial scale.     We have investigated methodology of extraction of BAS from tomato seeds under the action of cavitation ultrasonic field with the aim to reduce the extraction duration; the whole and milled seeds with the size of the particles of 0.2 – 0.3 m were used. The extraction process was performed using a 30% water-alcohol solution. The extraction procedure contains three stages: (1) cavitation treatment of seeds, (2) extraction of BAS according to the conventional method, (3) analysis of physico-chemical characteristics of the obtained extracts.     For the experiments the amplitude of ultrasonic extraction of ξ = 25 m, the time duration t = 60 min, and temperature T = 55 oC were used. The seeds were dryed on the paper in free air and then in a thermostate at a temperature of 100 oC until the constant mass. The results of determination of the quantity of the extracted BAS (mass, g) are presented in the Table. The analysis of the results shows that cavitation ultrasonic treatment generates a sonic capillary effect, induces a substancial solvent diffusion (water-alcohol solvent) in the cells of the seeds - both in whole and milled seeds. It was also shown that the extraction productivity is more efficient in the case of extraction of milled seeds. So it is necessary to use milled tomato seeds for extraction.