The antimetastaticactivity of ten compounds structurally related to nojirimycin A was examined using a pulmonary metastatic model of mouse B16 melanoma. Nojirimycin B, deoxynojirimycin, D-gluco-delta-lactam, CP3068 and CP3069 are structural analogues of nojirimycin A, and showed potent or moderate antimetastaticactivities. Nojirimycin A, nojirimycin B, deoxynojirimycin and D-gluco-delta-lactam showed