The roots of greater galanga are used as aphrodisiac in traditional edicine. However, their use has not been reported experimentally on scientific bases. herefore, this study was designed to investigate the effect of ethanolic extract of A. galanga (L.) Willed. roots on some cell lines and to diagnose this effect. The search for novel nticancer drugs is continuing. Agents that can eliminate the cancerous cells but don’t affect the normal cells may have a therapeutic advantage for the elimination of cancer cells. This work includes a preliminary study of the effect of A. galanga ethanolic rude extracts on four malignant human cell lines and one normal cell line. Ethanolic extract was prepared from dried roots of A. galanga to determine its anti tumor activity on four studied cell lines. Tested cell lines included human epidermoid larynx carcinoma (HEp-2), human rhabdomyosarcoma (RD), human glioblastoma multiform (AMGM5), murine mammary adenocarcinoma (AMN3) and normal rat embryo fibroblasts (REF). The ethanolic crude extract of greater galangal roots showed a time and dose - dependent effect on viability of HEp-2 cells. The highest three concentrations, (60, 125 and 250) μg/ml, showed both time and dose -dependent effects, while the highest concentration (250 μg/ml) gave the highest decrease in AMN3 cells viability (0.021) with inhibition reached (98.8%) after 72 hours. The ethanolic crude extract of greater galangal roots reduced the viability of RD cells gradually with time. The highest concentration (250 μg/ml) gave the highest decrease in AMGM5 cells viability (0.028) with inhibition reached (98.2%) after 72 hours. The ethanolic crude extract of greater galangal roots reduced the viability of REF cells very slightly after 72 hours. It is concluded that the AMN3 cell line was the most sensitive to the inhibitory effects of ethanolic crude extract of greater galangal roots while the AMGM5 cell line was the less sensitive to the inhibitory effects of the ethanolic crude extracts of greater galangal roots.