Calafate ( Berberis microphylla G. Forts) is an endemic plant from the Patagonian area of Chile and Argentina, with a high content of bioactive compounds. In this study the effect of ethanol-modified supercritical extraction at temperatures of 40 and 60 degrees C, pressures of 30 and 35 MPa, and azeotropic ethanol contents in CO2 of 5 and 10% on the yield of total solids (gravimetric method), alkaloids (spectrophotometric analysis), berberine (HPLC-DAD analysis), phenolics (spectrophotometric analysis), and antimicrobial activity (disc diffusion method) of calafate aerial parts, was evaluated. The yield of total solids increased with extraction temperature, pressure, and the percentage of ethanol in CO2. Berberine yield reached a maximum of 0.0211 f 0.46 g/kg substrate at 60 degrees C, 35 MPa, and using 10% ethanol. Extraction at 40 degrees C resulted in a higher phenolic content (1.69 f 0.02 g GAE/kg substrate) than at 60 degrees C. Limited antibacterial activity was observed in all obtained extracts with ethanol- modified supercritical CO2 against Staphylococcus aureus, with no significant difference between treatments. Ethanol-modified CO2 demonstrated moderate efficiency for extracting bioactive compounds from calafate aerial parts compared with Soxhlet extraction with azeotropic ethanol.