Recently there has been an increased interest in medicinal plants and their biologically active molecules. Medicinal plants are potential source for drug leads. Medicinal plants could substantially contribute to drug design and drug development.In this book, the taxanomy, phytochemistry and pharmacological activity of some key plant species used in ethnomedicine of different communities and ethnic groups have been reviewed as reported in available literature. The cumulative data in this book could be beneficial for those researchers who show interest in phytotherapy.