The article reviews the potential of epigallocatechin-3-gallate (EGCG), a major catechin found in green tea, to prevent various human diseases. EGCG functions as a powerful antioxidant, preventing oxidative damage in healthy cells and acting as an antiangiogenic and antitumor agent. It modulates tumor cell response to chemotherapy and induces apoptosis and cell growth arrest by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing oncogenic transcription factors and pluripotency maintenance factors. In vitro studies show that EGCG blocks carcinogenesis by affecting signal transduction pathways such as JAK/STAT, MAPK, PI3K/AKT, Wnt, and Notch. EGCG also stimulates telomere fragmentation by inhibiting telomerase activity. Clinical studies have demonstrated that EGCG treatment inhibits tumor incidence and multiplicity in different organs, including liver, stomach, skin, lung, mammary gland, and colon. EGCG reduces DNMTs, proteases, and DHFR activities, affecting transcription of tumor suppressor genes and protein synthesis. The review discusses EGCG's cancer preventive properties and its mechanisms of action, highlighting its safety, low cost, and bioavailability. EGCG's ability to inhibit cell proliferation, induce apoptosis, and modulate angiogenesis and metastasis makes it a promising non-toxic natural agent for cancer prevention and treatment.The article reviews the potential of epigallocatechin-3-gallate (EGCG), a major catechin found in green tea, to prevent various human diseases. EGCG functions as a powerful antioxidant, preventing oxidative damage in healthy cells and acting as an antiangiogenic and antitumor agent. It modulates tumor cell response to chemotherapy and induces apoptosis and cell growth arrest by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing oncogenic transcription factors and pluripotency maintenance factors. In vitro studies show that EGCG blocks carcinogenesis by affecting signal transduction pathways such as JAK/STAT, MAPK, PI3K/AKT, Wnt, and Notch. EGCG also stimulates telomere fragmentation by inhibiting telomerase activity. Clinical studies have demonstrated that EGCG treatment inhibits tumor incidence and multiplicity in different organs, including liver, stomach, skin, lung, mammary gland, and colon. EGCG reduces DNMTs, proteases, and DHFR activities, affecting transcription of tumor suppressor genes and protein synthesis. The review discusses EGCG's cancer preventive properties and its mechanisms of action, highlighting its safety, low cost, and bioavailability. EGCG's ability to inhibit cell proliferation, induce apoptosis, and modulate angiogenesis and metastasis makes it a promising non-toxic natural agent for cancer prevention and treatment.