The aim of the article was to study and model solvent effects on phytocompounds' extraction from Glycyrrhizae radix for substantiation of rational choice of the extractant in the technology of drugs obtained from this type of plant raw material. The process of extraction was carried out by simple maceration for 24 h at temperature 25°C ± 1°C and extractant/plant raw material ratio 5:1 (v/w). The content of hydro-ethanolic extracts based on ethanol solutions with concentration of 22, 41, 50, 71, 82, and 96% ± 1% v/v and some other solvents was studied by reversed phase high-performance liquid chromatography. The optimal range of solvent concentration for simultaneous extraction of chalcones and glycyrrhizic acid derivatives from Glycyrrhizae radix was determined. It was found that dielectric constant of the solvent plays a key role in the distribution process of phytocompounds between the phases; there is a certain range of dielectric constant values of the solvent-water solution, within which maximum phytocompound concentration in the extract can be observed; the dependency between phytocompound concentration in the extract and dielectric constant of the solvent-water solution can be described by equation lnC = a + b/ε+d/ε2.