Extraction of acrid and flavor compounds from horseradish and Wasabi with liquid- and supercritical carbon dioxide (SC-CO2) is described. It was possible to form acrid and flavor compounds by enzymatic reaction in liquid- and SC-CO2 as well as to extract them with liquid- and SC-CO2. A typical acrid component, allyl-isothiocyanate (AITC), formed enzymatically from a corresponding precursor was found to be separated from freeze-pulverized horseradish with CO2 at 20 MPa and 20°C without decreasing its peroxidase activity. Therefore, the residue after the extraction would be able to be used as a commercial source of peroxidase. The extracted AITC could be collected by forming the inclusion complex with β-cyclodextrin. The included AITC was very stable and is expected to be utilized as an additive to spices and foods.