Abstract: Cannabis plant material is extracted with a solvent matrix consisting of one or more organic solvents and optionally water. The cannabis plant material is agitated in the solvent matrix and then removed by filtration or centrifugation. Following extraction, the plant material is separated from the solvent matrix by centrifugation. The resulting extract is clarified by membrane filtration which also removes most of the water and water-soluble impurities. The resulting extract is dewaxed using membrane filtration and/or liquid-liquid extraction. Excess solvent and terpenoids are removed by means of molecular weight cutoff membrane filtration and the resulting cannabinoid solution is decarboxylated catalytically. Seed crystals are added to crystallize the cannabinoids.