This book offers a comprehensive review of the multifaceted role of phytochemicals in promoting human health and combating diseases. The initial chapters introduce phytochemicals, navigate the natural health landscape, and provide a foundational understanding of these bioactive compounds. The book unfolds the role of phytochemicals as a formidable defense against oxidative stress and explores the unique health benefits and nutritional significance of phytochemicals found in fruit peels. The subsequent chapters further discuss the therapeutic potential of phytochemicals, detailing their role in combating multidrug-resistant bacterial infections and modulating critical pathways in inflammation and cancer. This book also highlights the novel treatment strategies for amyloidosis using natural products, as well as the fascinating interplay between natural compounds and biogenic nanoparticles in the context of polycystic ovarian syndrome (PCOS). Further exploration includes the impact of plant-derived compounds on cancer stem cells and the recent advancements in ethnopharmacology for age-related brain disorders. Each chapter provides a thorough and up-to-date analysis of research findings, clinical applications, and future directions within the field. By presenting a holistic view of the diverse functions and benefits of phytochemicals, this book aims to inspire further investigation and innovation in this dynamic area of research, ultimately contributing to enhanced human health and well-being.