Colchicum species produce colchicine alkaloids which have been included in many pharmacopoeias. Colchicine relieves the symptoms of gout, and colchicoside, a glucosylated colchicine, is less harmful to human than colchicine. The glucosylated alkaloid is accumulated in the matured bulbs and seeds of Colchicum autumnale and the biological role of glucosylation may be the detoxication of colchicine alkaloid. The alkaloid-specific glucosylation probably occurs in the tissues during maturation. It is not known which of the four methoxyl groups of colchicine is replaced by an O-glucosyl residue in colchicoside (Fig. I). The position and the linkage configuration of the glucosyl residue are not known. This paper describes the linkage of the glucosyl residue of colchicoside isolated from the matured bulbs of Colchicum autumnale using enzymic hydrolysis and NMR analysis.