Two oligofurostanosides were isolated from the seeds of Asparagus officinalis L. and their structures characterized as 3-O-[α-L-rhamnopyranosyl-(1→2)-{α-L-rhamnopyranosyl-(1→4)}-β-D-glucopyranosyl]-26-O-[β-D-glucopyranosyl]-(25R)-22α-methoxyfurost-5-ene-3β,26-diol (methyl protodioscin) and its corresponding 22α-hydroxy analogue (protodioscin). The structural identification was performed using detailed analysis of 1H-and 13C-NMR spectra including two-dimensional NMR spectroscopy (COSY, HMQC, NOESY and HMBC), and chemical conversions. These two compounds have been shown to inhibit the growth of human leukemia HL-60 cells in culture and macro-molecular synthesis in a dose-dependent manner. The inhibitory effect on DNA synthesis was found to be irreversible.