The purpose of this study was to investigate the antiproliferative effect of the methanol and ethyl acetate extracts of Ornithogalum balansae flower and bulb against normal ARPE-19 cell line and cancer cell lines, A549, CRL-2923, HT-29 and HeLa. The cytotoxic activities of the extracts were determined using cell viability, deoxyribonucleic acid fragmentation and caspase-3 activity tests. Flower and bulb extracts exhibited dose-dependent antiproliferative effects on non-transformed and transformed cells, with greater growth inhibition in A549 lung cancer cells at lower concentrations. The IC50 values of the flower extracts against A549 cells were 1.5±0.153 and 2.2±0.503 µg/ml, and of the bulb extracts were 1.8±0.220 and 1.56±0.106 µg/ml, respectively. Against ARPE-19 cell line the IC50 values were 22.5±6.466 and 25±2.887 µg/ml for flower and 14±4.726 and 12.5±3.182 µg/ml for bulb extracts, respectively. In addition, it was observed that at concentrations ≤3.12 µg/ml there were statistically significant differences between ARPE-19 and transformed A549 cell lines (p