A new aristolactam, named enterocarpam-III (10-amino-2,3,4,6-tetramethoxy phenanthrene-1-carboxylic acid lactam, <strong>1</strong>) together with the known alkaloid stigmalactam (<strong>2</strong>), were isolated from <em>Orophea enterocarpa</em>. Their structures were elucidated on the basis of interpretation of their spectroscopic data. Compounds <strong>1</strong> and <strong>2</strong> exhibited significant cytotoxicities against human colon adenocarcinoma (HCT15) cell line with IC₅₀ values of 1.68 and 1.32 μM, respectively.