Flavonoids are natural compounds that possess therapeutic value is ethnobotany or ethnopharmacology. Anti-viral/bacterial, anti-inflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging properties have long been received great attention and well supported by various studies. Their basic structures consist of C6-C3-C6 rings with different substitution patterns to produce a series of subclass compounds such as flavones, flavonols, flavanones, isoflavones, flavanols or catechins and anthocyanins. Many flavonoid compounds are shown to have an antioxidative activity, free radical scavenging capacity. This review includes selected flavonoids, their sources and various activities.