Cancer remains one of the leading causes of mortality worldwide despite major advances in chemotherapy, radiotherapy, and targeted therapies. Limitations associated with conventional treatments, including systemic toxicity, drug resistance, tumour recurrence, and high treatment costs, have stimulated interest in alternative and integrative therapeutic approaches. Traditional medicinal systems, particularly Siddha medicine, offer a holistic perspective in disease management through restoration of physiological balance, detoxification, and rejuvenation. In Siddha literature, cancer-like conditions (Putru Noi) are associated with disturbances in the three humours—Vatham, Pitham, and Kapham—along with impaired metabolic activity (Agni) and accumulation of toxins (Ama).

Boerhavia diffusa (Punarnava), an important medicinal herb used in Siddha medicine, has attracted considerable scientific attention because of its diverse pharmacological properties. The plant contains several bioactive phytoconstituents, including flavonoids, alkaloids, retinoid, phenolic compounds, lignin’s, and phytosterols, which contribute to its antioxidant, anti-inflammatory, immunomodulatory, anti-proliferative, anti-metastatic, and apoptosis-inducing activities. Experimental studies have demonstrated that Boerhavia diffusa modulates multiple molecular pathways involved in carcinogenesis, including NF-κB, PI3K/Akt, VEGF, mitochondrial apoptotic pathways, and matrix metalloproteinases (MMPs). These mechanisms collectively contribute to inhibition of tumour growth, suppression of metastasis, induction of apoptosis, and reduction of oxidative stress and inflammation.

The present review critically examines the botanical, pharmacognostic, phytochemical, pharmacological, and therapeutic significance of Boerhavia diffusa in cancer management from both Siddha and modern biomedical perspectives. In addition, the review discusses its potential role in integrative oncology as a complementary therapeutic agent capable of enhancing immune response, reducing treatment-associated toxicity, and improving patient quality of life. Although preclinical findings strongly support its anticancer potential, further clinical studies, standardization of formulations, and safety evaluations are necessary before its widespread therapeutic application. Overall, Boerhavia diffusa represents a promising bridge between traditional Siddha knowledge and evidence-based modern oncology, offering potential for the development of safer and multi-targeted cancer therapies.