The phenolic profile, antioxidant activity and cytotoxicity of O. aucheriana aqueous extract were investigated. HPLC-DAD (high performance liquid chromatography-diode array detector) technique was used to define the profile of phenolic compounds of the resultant extract. Antioxidant properties were evaluated using different methods, including phosphomolybdenum, free radical scavenging and lipid peroxidation assays. Rosmarinic, gallic and p-hydroxybenzoic acids were determined as the major phenolic compounds. Human rhabdomyosarcoma (RD), human cervix carcinoma (Hep2c) and murine fibroblast (L2OB) cell lines were used to examine the cytotoxicity of the extract. The IC50 (inhibitory concentration at 50%) values ranged from 25.54 to 40.34 μg/mL. These results suggest that this species may be considered as a valuable candidate for preparing new food and drug formulations.