In this paper the essential oil supercritical carbon dioxide extraction from leaves of Lamiaceae family species was studied. Recent investigations of Lamiaceae family essential oil storage have shown that most of the oil is found in peltate glandular trichomes on the leaf surface. The effect of supercritical CO2 on the peltate glands was investigated by Scanning Electron Microscopy. It was observed that exposure to supercritical CO2 led to disruption of the peltate glands and essential oil release. This phenomenon was used as a basic hypothesis of the mathematical model of the supercritical fluid extraction with CO2. The model was applied to simulate basil, rosemary, marjoram and pennyroyal supercritical CO2 extraction on the existing experimental data. An average deviation from the experimental data was less than 0.83%. The model results indicated a possibility of a decrease in the supercritical CO2 consumption by modified and optimized processing of Lamiaceae family herbaceous material. (c) 2005 Elsevier Ltd. All rights reserved.