In this study, cytotoxic effects of the dichloromethane, ethyl acetate, ethanol, and aqueous extracts of the aerial parts of Cyclotrichium niveum (Boiss.) Manden. & Scheng (Lamiaceae) were evaluated. We tested HeLa, MCF-7 cancer cells, and MRC-5 and MCF-10A normal cells. The ethyl acetate and dichloromethane extracts induced cytotoxicity whereas the ethanol and aqueous extracts had no cytotoxic activity against both cancer cells. IC50 values of the dichloromethane extract were 353.0 +/- 8430 Ag/ml, 114.8 +/- 40.34 mu g/ml, 39 +/- 0.56 mu g/ml, and 49 +/- 13 mu g/ml in HeLa, MCF-7, MRC-5, MCF-10A cells, respectively. IC50 values of the ethyl acetate extract were 117.0 +/- 36.24 mu g/ml in HeLa cells, 1563 +/- 19.86 mu g/ml in MCF-7 cells, 1100 +/- 340 mu g/ml in MRC-5 cells and 7900 +/- 1200 mu g/ml in MCF-10A cells. Additionally, the ethyl acetate extract showed more selectivity to HeLa and MCF-7 cancer cells than MRC-5 and MCF-10A normal cells. Our results of HPLC analysis showed that apigenin in the ethyl acetate extract (2.2518 +/- 0.0005 mu g/100 mg extract) might be responsible of that selective cytotoxic effect. In the current work, we have shown for the first time that C niveum has cytotoxic properties in the cancer cell lines tested. (C) 2017 Elsevier Ltd. All rights reserved.