Book excerpt: This book is designed to provide pharmacologists and researchers of natural products a comprehensive review of 200 medicinal plants, their vernacular names in various languages and their medicinal uses around the world, and in some cases, a historical perspective. Chemical constituents of each plant with the putative active constituent, and available up to date pharmacological studies (until 2017 on PubMed) with each medical activity explored and its relationship with traditional uses, are described for each plant. Any variations in chemical constituents and their effects on pharmacological studies outcome have been highlighted. All clinical trials conducted, with sufficient details, have been included. Nationalities and racial identities of participants of clinical trials are identified to impress upon the social, cultural and dietary influences on the clinical outcomes. Toxicity studies and potential interactions with prescribed drugs, and full spectrum of references are included.