This book reviews the applications of polyphenols in cancer treatment. The initial chapter of the book classifies different polyphenols and discusses their biological and chemical properties. The subsequent chapters then explore the diverse role of polyphenols in modulating signal transduction pathways in cancer including, cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis, and metastasis. This book highlights the usefulness of polyphenol enriched seafood in modulating the anti-tumor and anti-inflammatory cytokine IFN-γ. The book also presents nanoformulation of polyphenol as a promising strategy for their enhanced bioavailability and targeted delivery. Lastly, the book examines the toxicity and safety evaluations of polyphenols as anticancer agents.