Vinorelbine (NVB) is a newly synthesized vinca alkaloid that has been used to treat advanced malignant diseases including lung adenocarcinoma and lymphoma. The effect of NVB on myeloma, however, is unknown. We therefore examined the effect of NVB on the growth of human myeloma cell lines (RPMI8226, U266 and KPMM2) using the trypan blue dye exclusion test and Alamar blue assay. NVB inhibited the growth of myeloma cells of all three cell lines dose-dependently and this effect was intensified when NVB was combined with dexamethasone at 1.0 x 10(-6)mol/l. Flow cytometric analysis using annexin V (AN) and 7-amino-actinomycin D (7AAD) showed that NVB-induced apoptosis of these myeloma cells in all the cell lines. NVB appears to be a potent inducer of apoptosis in myeloma cells, and might have some benefit in the treatment of myeloma patients.