Flavonoids are the natural poly phenolic secondary metabolites of plants widely distributed in plant kingdom, which are responsible for the various colors of bark, leaves, flowers, fruits and seeds. Flavonoids are now considered as an indispensable component in a variety of nutraceuticals, pharmaceuticals, medicinal and cosmetic preparations. They possess potentially antioxidant property and versatile fields of the health benefits. Moreover flavonoids have sedative, antidepressant, anticonvulsant, anti-proliferative, anti-inflammatory, anti-microbial, anticancer, cardioprotective, antihypertensive, antiulcerogenic, antidiabetic and hepatoprotective activities. These pharmacological effects are mainly due to their antioxidant property. Also flavonoids have effect on mammalian enzymes like protein kinases, alpha-glucosidase and aldose reductase, and thereby they regulate multiple cellular signaling pathways that are altered during disease conditions. A number of flavonoids are available in the market as pharmaceutical products because of its potent and extended pharmacological activities, higher safety profile, low toxicity and cost effective bulk production. The present review is focused on the pharmacological and biological effects, and mechanism of action of flavonoid compounds along with slightly lighting other significant properties.