Objective: To determine the inhibition activity of Typhonium flagelliforme Lodd. Blume (T. flagelliforme) leaf extract on cyclooxygenase 2 (COX-2) expression of colon cancer cells. Methods: T. flagelliforme leaf extract was prepared to macerate in ethyl acetate. In vitro anticancer activity was assayed by MTT method on WiDr colon cancer cells. This study applied apoptosis induction assay to investigate the mechanism of cell death using double staining method. COX-2 expression was stained by immunocytochemistry. Results: T. flagelliforme showed anticancer activity and induced apoptosis on WiDr cells through inhibition of COX-2 expression with IC