In present work the extraction of feverfew flower heads was performed using supercritical carbon dioxide at pressures from 200 to 800 bar and at temperatures of 40, 60 and 80degreesC. For comparison, the conventional extractions with organic solvents have been performed. Dry feverfew flower heads were used as starting material. Supercritical fluid extraction (SFE) was performed using a semi continuous flow apparatus in a laboratory and pilot scale. The influence of process parameters on the total yield and amount of parthenolide isolated was investigated. Dynamic behaviour of the extraction runs followed by single-step separation was analysed by a mathematical model for initial constant rate extraction period and the subsequent time-dependant diffusion controlling mass transfer rate period. In order to concentrate the obtained extract in parthenolide, a two-step separation was employed. (C) 2004 Elsevier B.V. All rights reserved.