This review brings out some medicinal plants that have therapeutic potential due to the presence of natural antioxidants. Majority of their antioxidant activity is due to bioactive compounds viz. Flavonoids and Polyphenolic compounds. The Present research reveals that Flavonoids and polyphenolic compounds activity have important effects on cancer chemoprevention and chemotherapy. Numerous mechanisms of action have been recognized, along with inactivation cancer, antiproliferation, and cell cycle arrest, stimulation of apoptosis and inhibition of angiogenesis. This work has particularly enhanced the function of antioxidants activity of Flavonoids for cancer research. Key word: Flavonoids, Antioxidant, Free radical and Cancer research