The titled book, “Textbook of Pharmacology I” (As per PCI regulation). The idea of book originated by authors to convey a combined database for easy understanding of Pharmacology. This book is intended to communicate information on pharmacology, to direct tutors and learners regarding fundamental concepts in Pharmacology I. The major aim to write this textbook is to provide information in articulate summarized manner to accomplish necessities of undergraduates as per PCI regulation. This volume is designed not only according to curriculum of undergraduate courses in pharmacy by PCI but also to communicate knowledge on Phamacology for post graduate learners. We assured this book will be originated very valuable by graduates, post graduates, professors and industrial learners.