Objective: To survey K-RAS blocker of choice among a group of inhibitors with characterizing their safety profile in colorectal carcinoma. An experimental model of continuous SW480 cell line and Vero cell line was applied, in vitro assessment by using tissue culture as a standard technique for checking the cytotoxicity of many compounds and in development of new drugs. Materials and methods: This study tested the cytotoxicity assay of MEX2R and chemotherapy (methotrexate) as comparative agents in the mechanism of action with the tested drug by Crystal Violet assay (CV). After exposure both SW480 cell line and Vero cell line were treated first to different concentrations of MEX2R compound (15.625, 31.25, 62.5, 125, 250 and 500) μg/ml for 36 hours and secondly to different concentrations of methotrexate (15.625, 31.25, 62.5, 125, 250 and 500) μg/ml for 36 hours. Results: The results showed that the investigational agent MEX2R exhibits highly significant cytotoxic effects (p ≤ 0.05) in SW480 colorectal cancer cells when compared with control (untreated cells), and less cytotoxic influences on normal Vero cell line in a dosedependent manner. The tested drugs showed anticancer activity with half maximal growth inhibitory concentrations (IC50) for MEX2R 65.738 μg/ml which was more potent than antitumor drugs methotrexate (MTX) that has cell cycle arrest activity like investigational agent’s action, IC50 of MTX was about 93.574 μg/ml. The selectivity index of MEX2R compound (3.252) was higher than the selectivity index of MTX (2.65). Conclusion: From the overall results, MEX2R has highly significant cytotoxic effects on SW480 colorectal cancer cell line when compared with MTX, also MEX2R agent possessed safe profiles in Vero cell line as normal cells in comparison with standard chemotherapy MTX.