Natural products have a long history of use as folk medicines in several systems of traditional medicine. Extensive evidence from modern pharmacological studies has confirmed traditional applications, and unveiled the vast potential of naturally occurring compounds, particularly plant-derived phytochemicals, in the management of chronic human diseases. The past decade has witnessed a surge of findings from randomized controlled trials testifying the safety and efficacy of natural products as adjuncts or alternatives to standard-of-care medications for several illnesses. Biomolecular studies have unveiled hundreds of cellular and molecular targets for phytochemicals including key transcription factors, receptors, enzymes, hormones, neurotransmitters, cytokines, lipids, and non-coding RNAs. Extensive research on the preventative and therapeutic effects of natural products necessitates regular updating of the literature as to the developing potential roles of these compounds in different human diseases. This new book provides an overview of the current pharmacological and clinical features of natural products, and the role of phytopharmaceutical compounds in health and diseases. Chapters cover a wide scope, from cancers, to chronic and age-related disorders, and are written by leading international subject experts. Collectively, chapters will provide useful insights on the regulatory effects of phytochemicals and nutraceuticals on pathogenic molecular signatures associated with pathologies, disease biomarkers, and aging-related pathways.