Extraction of valerenic acids (valerenic, acetoxyvalerenic and hydroxyvalerenic) from dry ground rhizomes of valerian (Valeriana officinalis L.) was studied. The effect of ethanol concentration in the solvent, extraction temperature and drug particle size on extraction kinetics were investigated and the optimum values of these process parameters were determined for the case of intensively stirred two-phase dispersion. It was found that increased processing temperature favors extraction kinetics, but provokes moderate degradation of valerenic acids.