**Abstract**

Medicinal plants were shown to play a significant role in curing many diseases of ancient times. The plant kingdom is truly a goldmine of potential drug compounds. Several earlier reviews and research studies summarized that the products from natural sources have contributed significantly to the discovery of drugs and health benefits for people. Moreover, it is believed that natural products are less deadly than synthetic medicines because of their plant origins. Medicinal plants are significant in the role of curing a variety of diseases and the properties that they possess for curing are related to the existence of phenolic compounds, flavonoids, anthocyanins and other phytochemicals. This chapter covers the effects of phenolic compound on plants and the importance of phenolic compounds for human health for prevention of various oxidative stress associated diseases.

**Keywords:** Medicinal Plants, Phenolic Compounds, flavonoids, stilbenes, lignans and phenolic acid
