The alkaloids colchicine and colchicoside contained in meadow saffron (Colchicum autumnale L.) seeds are used, respectively, in drugs to treat gout and relax muscles. A two year study at two sites demonstrated the concentration and yields of these two seed constituents involves the transformation of colchicine into colchicoside during plant growth. The optimum harvest date for meadow saffron could be selected for the highest total alkaloid or colchicoside content and for the highest dry matter, and alkaloid yields. Differences in alkaloid yields and concentrations in different plant parts strongly suggest that alkaloids can be translocated in the plant.