This work investigates the supercritical CO2 extraction of capsidiol from pepper fruit tissues activated with Alternaria alternate (Fr) Keissler suspension culture as a biotic elicitor. Capsidiol production in the fruit tissue was markedly increased by the treatment with a biotic elicitor and reached its maximum level after 4 days of elicitation. The effects of separation parameters such as temperature, pressure, supercritical solvent flow rate, particle diameter and also initial capsidiol concentration were investigated on solubility, initial extraction rate and extraction yield. The optimal extraction conditions were obtained at the temperature of 40degreesC, the pressure of 400bar, the supercritical CO2 flow rate of 2 cm(3) min(-1), and the average particle diameter of 116mum. The results showed that the ratio of the supercritical CO2 extraction yield to the organic solvent extraction yield was changed from 84 to 97 wt-% depending on the initial capsidiol concentration. (C) 2004 Society of Chemical Industry.