The present study aimed to evaluate in vitro anti-cancer activity of Ochradenus baccatus leaves extract on various cell lines. The second aim determination of the total phenolic, flavonoid contents, and antioxidant potential from the methanol extract of O. baccatus leaves collected from El-Shaikh Fadl - Ras Gharib Road in the Eastern Desert of Egypt. The anti-proliferation activity of O. baccatus extract was tested by SRB assay on five different cell lines: HEPG2 (liver hepatocellular carcinoma cell line), HCT (Colon carcinoma cell line), MCF7 (breast carcinoma cell line), HEP2 (Larynx carcinoma cell line), and H1299 (Lung carcinoma cell line). Total phenolics, antioxidants, and flavenoid contents were determined in the extract of the xerophytic O. baccatus plant and the fluctuation of these contents due to environmental variations. Indicated that incubation of HEP2 in the extract of leaves attained the highest values of IC50 (47.8 μg/ml.), while the lowest (215 μg/ml.) was attained furthermore, the highest and the lowest growth inhibition percentages (GIP) (82.81 and 54 %) were observed with HEP2 and MCF7, respectively. Also, results showed the highest total flavenoid contents in O. baccatus leaves was during the winter season. Summer conditions exhibited the highest contents of total phenolic compounds accompanied by significant increases in Ca+2, Mg+2, and Na+ contents in leaves. We concluded that O. baccatus is a rich source of polyphenolic and flavonoid compounds with good antioxidant properties that help in the prevention and therapy of various oxidative stress-related diseases such as cancer and hepatic diseases.