Apigenin is one of the most bioactive naturally occurring flavonoids, found in fruits, plant-derived beverages, vegetables, wheat sprouts, and some seasonings. It has been found to possess anti-oxidant, anti-inflammatory, and anti-cancer properties. Naringenin is one of the most studied flavonoids abundant in citrus plants. Naringenin and their derivatives are known to exhibit strong anti-oxidant potential along with plenty of protective effects for the improvement of human health. This book discusses the natural sources, pharmacology and role in cancer prevention of the flavonoids, apigenin and naringenin.