A new acridone alkaloid, named 9-hydroxynoracronycine (1), together with four known compounds, including coumarins, lignan, and indole alkaloid, was isolated and identified from the roots and rhizomes of Rauvolfia verticillata. The structure of the new compound was determined by spectroscopic means (UV, IR, MS, and NMR). The acridone alkaloid and coumarins were identified as new constituents of Rauvolfia genus. The cytotoxic activities of the new compound were tested against human breast cancer cell line MCF-7 and human promyelocytic leukemia HL-60. Results showed that compound 1 decreased MCF-7 cell proliferation in a statistically IC50 significant manner at 102.8 mu mol/L. In addition, compound 1 exhibited moderate small intestine smooth muscle relaxation.