Micronized cholesterol particles were produced via the Rapid Expansion of Supercritical CO2 Solutions (RESS) process. Taguchi design was used for designing the experimental plan to investigate the effects of three parameters including extraction temperature (40-60 degrees C), extraction pressure (100-160 bar) and nozzle diameter (0.15-0.24 mm) on the size and morphology of the cholesterol particles produced by the RESS process. The characterization of the particles was carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements to evaluate the performance of RESS process. The average particle size of the original material was 55 mu m +/- (2.84) while the average particle size of cholesterol after size reduction via the RESS process was between the minimum of 0.62 mu m +/- (0.03) and the maximum of 4.83 mu m +/- (0.18) depending upon the experimental conditions used. It was observed that both increasing the temperature from 40 to 60 degrees C and increasing the nozzle diameter from 0.15 to 0.24 mm result a reducing effect on the average particle size, whereas extraction pressure (100-160 bar) change has slight effect on the average particle size. (C) 2011 Elsevier B.V. All rights reserved.