Five cholestane glycosides (1 - 5) including three new ones (3 - 5) with potent cytostatic activity on leukemia HL-60 cells were isolated from Ornithogalum saandersiae bulbs. Compound 1, a main constituent in the bulbs, was revealed to be exceptionally cytostatic against various malignant tumor cells and effective to mouse P388 leukemia in in vivo evaluation.