Cancer continues to be a fatal disease accounting for millions of deaths worldwide. The heterogeneity of tumours in cancer patients, as well as resistance of cancer cells to apoptosis and chemotherapeutic agents poses tremendous challenges in its prevention and treatment, often causing cancer relapse. Conventional chemotherapeutic drugs adversely affect normal, healthy cells causing hepatotoxicity, neurotoxicity, cardiotoxicity, nephrotoxicity, and accelerated aging in cancer patients. Plant-based drugs, vincristine, vinblastine and paclitaxel remain the most effective anticancer agents, but their therapeutic uses are limited by myelosuppression, drug resistance and cytotoxicity, making it imperative to search for novel, safe, chemopreventive and chemotherapeutic drugs to mitigate the morbidity and mortality associated with cancer. The review accentuates the potential of four promising Indian traditional medicinal plants, Curcuma longa, Withania somnifera, Piper longum, Andrographis paniculata, and their bioactive compounds which exhibit significant anti-inflammatory, anti-proliferative, anti-angiogenic, anti-metastatic and pro-apoptotic effects, against diverse cancer types, in several pre-clinical studies. Adjunct therapies with these promising plant extracts/ phytochemicals can prevent the progression of cancer, potentiate the therapeutic effects of conventional drugs, attenuate their toxicity, minimize drug resistance, and improve the quality of life of cancer patients.