Abstract: The invention relates to a process for the preparation of colchicine 1 from colchicoside 2 which comprises enzymatic conversion of colchicoside 2 to 3-O-demethylcolchicine 3, wherein the enzyme used is a cellulase. According to another aspect of the invention, 3-O-demethylcolchicine 3 can be converted to colchicine 1 using an alkylating agent. The invention also relates to a process or enriching the colchicine 1 content of extracts from plants belonging to the Colchicaceae family containing colchicine 1, colchicoside 2 and 3-(9-demethyl colchicine 3, which comprises conversion by means of a colchicoside 2 cellulase to 3-O-demethylcolchicine 3, followed by conversion of 3-O-demethylcolchicine 3 to colchicine 1 using an alkylating agent.