Medicinal plants produce various bioactive molecules with potential anticancer properties with favorable safety profiles. We investigated the comprehensive composition of Vernonia amygdalina leaf extract and its cytotoxic effects via apoptosis in HeLa cells. The metabolomics approach was conducted to gather the metabolite profile of the extract. Proteomics was performed to understand the comprehensive mechanistic pathways of action. The apoptosis was visualized by cellular staining and the apoptotic proteins were evaluated. V. amygdalina leaf extract exhibited dose-dependent cytotoxic effects on both HeLa and Vero cells after 24 h of exposure, however, a higher concentration was required for Vero cells cytotoxicity. The metabolomic profile indicated that majority of metabolites were alkaloids, phenolic compounds, and steroids. The cytotoxic pathways involved the response to stress and cell death which was similar to doxorubicin. The upstream regulatory proteins, PTEN and XBP1, were significantly altered supporting the regulation of apoptosis and cell death. The levels of apoptotic proteins, JNK, p53, and caspase-9 were significantly increased. These provided strong evidence that V. amygdalina leaf extract related to the induction of apoptosis and highlighted its potential for the development of chemotherapy.