Melothria heterophylla (Lour.) Cogn., (family-Cucurbitaceae) popularly known as kundari, has been shown to exhibit antioxidant effects. The main objective was to isolate active constituents of the plant extract. In this study, the ability of M. heterophylla to induce apoptosis was studied in Ehrlich ascites carcinoma cells. Treatment of the Ehrlich ascites carcinoma cells with a variety of concentrations of the ethanol extracts of M. heterophylla and gallic acid (100-1000 μM), to determine the sequences of events marked by apoptosis, assayed by the spectrofluorometric method. Gallic acid and rutin were isolated from plant extract which were quantified by high-performance liquid chromatography. Our results indicate that ethanol extracts of M. heterophylla and gallic acid-induced apoptotic cell death in a dose dependent manner could be due to the generation of reactive oxygen species, especially H 2O 2, which is confirmed by caspase 3 activation. Treatment of Ehrlich ascites carcinoma bearing Swiss albino mice with varied doses (200 and 400 mg/kg, b.w.) of plant extract significantly reduced tumor volume and viable tumor cell count and improved hemoglobin content, RBC count, mean survival time, tumor inhibition, and percentage life span. The enhanced antioxidant status in extract-treated animals were evident from the decline in the levels of lipid peroxidation and increased levels of glutathione, catalase, and superoxide dismutase. The data suggest that M. heterophylla exerts anticancer activity, valuable for application in food and drug products.