Abstract: The invention provides a method and system for extracting desired compounds from a plant or a plant based material featuring a) providing a plant or plant based material; b) pumping CO2 gas from a CO2 storage vessel into an apparatus containing a CO2 circulation loop; c) circulating CO2 through the plant or plant based material in the circulation loop; d) extracting the desired compounds; and e) discharging the CO2 gas from the CO2 circulation loop. The circulation loop may have a separator vessel and an extractor vessel, the desired compound may be a terpene, tetrahydrocannabinol (THC) or carbenoxolone (CBx), and the CO2 may be circulated as a supercritical CO2.