The powerful antioxidative and HeLa cytotoxic activity of crude ethanol extract of Curcuma comosa Roxb. prompted us to carry out biologically-guided separation of the active constituent. Chromatographic separation of the ethanol extract yielded fractions Zcc(R)-E-1 and Zcc(R)-E-2. The potent fraction Zcc(R)-E- 1 was subsequently bioassay-guided separated and the active fraction Zcc(R)-E-15 was obtained.Recrystallization of fraction Zcc(R)-E-15 yielded compound A, exhibited antioxidant power 1064.73 ± 60.96 μM vitamin C equivalenceand HeLa cell cytotoxicity with IC50 4.44 ± 0.85 μg/ml. With structure elucidation via spectroscopic techniques, compound A was identified as 4,6-dihydroxy-2-O (β-D-glucopyranosyl)acetophenone.