The effect of ultrasound (US) application on pyrethrins extraction from dried Pyrethrum flowers (Chrysanthemum cinerariae folium) is studied. Extraction experiments, using hexane as solvent, are carried out in two agitated glass extractors, equipped with: a) a central US generating probe and b) six lateral US emitters. It is found that the US application has positive effect, which is stronger than the effect of the temperature increase from 20 degrees C to 40 degrees C, in particular during the initial extraction period. This is explained by the cavitation phenomena occurring in the particle pores. It is shown also, that the extraction efficiency is directly related to US energy input in the system and does not depend on the way the US vibrations are generated.