The incidence of colon cancer in Indonesia is relatively high. Colon cancer treatment has many side effects. Therefore it needs to develop colon cancer drugs from natural ingredients such as roselle calyx (Hibiscus sabdariffa L.) as chemopreventif to increase efficacy and reduce the side effects. This study aims to know potential of ethanol fraction of roselle calyx (FEBR) that contains flavonoid cyanidin-3-sambubioside as antioxidant, cytotoxic and ability to inhibit the growth of cancer cells. The methode used are in vitro and in silico.Roselle calyx maserated and fractionated Thin layer Chromatography (TLC) used to identfication flavonoid in FEBR qualitatively. Antioxidant Test FEBR measured by DPPH. Cytotoxicity test in WiDr cell line to find out cell viability by MTT Assay method. Life cycle of each cell is analyzed to find out the cell cycle phase with Flowsitometric method. Molecular docking of FEBR with active compound cyandin 3-sambubioside in IKK and VEGF with Autodock Vina method. The TLC result for flavonod in FEBR showed dark violet and violet spot in UV 366. Antioxidant and cytotoxic test of FEBR have weak ability with each IC50 428 μg/ml and 3127 μg/ml. Cell cycle inhibition on each cell occurs in the M1 phase. Molecular docking’s results showed that inhibitory activity of FEBR in IKK and VEGF with affinity energy -9.6 kcal/mol dan -6.7 kcal/mol.