World Health Organization WHO documented that more than three-fourths of the communities in resource limited countries rely upon medicinal plants for their primary health care needs because more than 60% of the societies are unable to afford allopathic medicines. This book is about pharmacognostic and pharmacological approaches to drugs, crude drugs, drugs from both natural and synthetic sources but in this book main concern with drugs from natural sources in which on pinnacle is plant based include alkaloids, Glycosides, fixed oils, volatile oils, tannins and resins as well as drugs from animal sources and microorganisms.