The extraction process of medicinal raw materials, as a rule, includes two phases:
* osmotic swelling with dissolution of the cell contents (movement of the solvent into the cell);
* extraction, in which extractive substances are transported from the cell through the cell membranes, pores and capillaries into the volume of the solvent. The swelling process, on average, lasts up to 6..10 hours, and depends on the rate of air displacement from the cell. In addition, some of the air remains inside the cell.

When using ultrasound, a sound capillary effect takes place, which not only accelerates the displacement of air bubbles, but also creates conditions for their dissolution in liquid. As a result, there is a sharp reduction in the process of swelling of raw materials. The efficiency of the extraction process is influenced by the morphological and anatomical structure of the raw material and its dispersion.