Breast cancer is one of the most common cancers that causes the highest morbidity and mortality in woman at Indonesia. Some anticancer medicines are not efficient and also have many side effects then needed cancers treatment based on nature one of them use bandotan as chemopreventive agent. Previous research on bandotan used various fraction and cancer cells then it’s necessary further research about bandotan as anticancer. This study aimed to analyze the cytotoxic activity of n-hexane fraction bandotan (NFB) in breast cancer cells MCF-7 in vitro and study the molecular mechanism of the active component NFB in silico, with the target protein HER-2. Identification of the compounds content in bandotan by Thin Layer Chromatography (TLC). Antioxidant Test NFB measured by DPPH and cytotoxicity assay NFB performed with MTT, test carried out by molecular docking protein preparation and docking test compounds ageratochromene on HER-2. Based on the research of 1.2 kg to obtain NFB concentrated 1.7 gram which will then be tested TLC, check the antioxidant and cytotoxic test. The test results of TLC showed that bandotan has alkaloid and steroid content, antioxidant activity of NFB showed with value of IC50 493 μg/ml and potential bandotan as a cytotoxic agent is mediated by the ability of ageratochromene inhibit HER-2 protein targets with affinity -6,2 kcal/mol. Cytotoxic potential of NFB with an IC50 value of NFB 306 μg/ml to inhibit the growth of MCF-7 cells line. From the result obtained can be said that NFB has a weak potential as chemopreventif for breast cancer MCF-7 cell line.