Asteraceae family plants have potential anticancer activity. In this study, the cytotoxic effects of C. iconica were investigated using different tumor cell lines: Non-small lung cancer (A549) and human endometrium carcinoma cell line (RL95-2). The cytotoxicity of the extracts was determined with MTT assay and the xCELLigence Real-Time Cell Analyser (RTCA). As a result, the ethyl acetate sub-extract and methanol extract of C. iconica were found cytotoxic to RL95-2 cell line with 271 and 51 µg/mL IC50 values, respectively. According to RTCA results, the IC50 values of ethyl acetate sub-extract were 44.82, 60.89, and 55.22 µg/mL and methanol extract 265.52, 250.48, and 246.65 µg/mL, for 24, 48, and 72 h exposure, respectively. RL95-2 cells are more sensitive to ethyl acetate sub-extract than methanol extract. This study is the known first study to show the cytotoxic effects of C. iconica extracts on both A549 and RL95-2 cell lines.