Medicinal Chemistry is concerned with chemistry, synthesis, and structure activity relationships, mode of action and uses of drugs of carbon compounds. There are several books are available on medicinal chemistry, the material in most of them is present in a diffused form or highly specialized. In the ever expanding knowledge of the chemistry of drugs it is very difficult to go through the various textbooks, journals, and pharmacopoeias. Medicinal Chemistry has virtually widened the scope to tackle all vital aspects related to such super specialties as: Bulk Drug Industry, Small Scale Drug Manufacturing Units, R & D Laboratories in Pharmaceutical Industries; PG/Ph.D., Research Scholars.  In this book we have describe the basic concept   behind the physiochemical properties affecting on drug properties, their action and synthesis which are useful to various graduated and undergraduate students.