Growth inhibitory activity of YM881 (SMANCS) against 3 human cultured cell lines and one rat cultured cell line derived from glioma cells was assessed quantitatively. YM881 showed potent cytotoxicity against all glioma cell lines tested; the IC50 of this drug was 1.9-8.4 micrograms/ml. YM881 may be classified as a concentration-dependent drug but it has also a time-dependent effect. Flow cytometric studies of the DNA histogram showed accumulation in the G2-M phase with YM881. These findings suggest that YM881 may be useful in the treatment of glioma.