Capillary SFC of basic drugs of abuse have been studied using two different columns, and the results were compared with GC. These results have proved the ability of supercritical CO2 to solubilize and extract basic drugs of interest. A novel restrictor has been used to control precisely the flow rate through the extraction cell over a long period of time. Optimal conditions for quantitative recoveries of aqueous morphine adsorbated on C18 silica by SFE has been determined. Recoveries of 100% with a variation of 2% was obtained with an extraction time of 25 min. The influence of the pressure, solvent modifier, and flow rate of extraction fluid on the extraction efficiency was determined. These conditions were also found to be applicable for extracting other drugs of abuse.