In this book, the authors present current research in the study of the role in agriculture, health effects and medical applications of plant extracts. Topics discussed include the risks and benefits of phytochemicals present in fruits and vegetables; medicinal plants and their pharmacological attributes; Moringa oleifera and its benefits in nutrition and health; the potential health benefits and applications of the agave species; herbal medicinal plants used in the treatment of diabetes in Africa; phenolic compounds extracted from medicinal plants as an alternative for cancer prevention and treatment; using the antifeedant and repellent effects of plant extracts in the protection of plants and human health; essential oils and extracts of medicinal plants in the control of diseases in plants; herbal therapies for dermatological disorders; polyphenols as a source of antimicrobial agents against human pathogens; and new trends in plant extract use for food-borne pathogenic bacterial control.