Phytochemicals have been present in human diet and life since the birth of mankind, including the consuming of plant foods and the application of herbal treatments. This coevolutionary interaction of plants and people has resulted in humans' reliance on food and medicinal plants as sources of macronutrients, micronutrients, and bioactive phytochemicals. Phytochemicals can be used as adjuvant agents and sensitizers in traditional antibiotic and anticancer therapy, reducing the potential of selecting resistant microbial strains and cancer cells. Recent Frontiers of Phytochemicals addresses the many processes of potential phytochemical evaluation of known sources, with a focus on phytochemical and pharmacological evaluations, and computational research into the structures and pharmacological mechanisms of natural products and their applications in medicine, food and biotech.