This book aims to be a textbook for the Undergraduate students of Pharmacy. The book provides a comprehensive, balanced introduction and detailed information on the various classes of drugs used in Pharmacy. The approach to medicinal chemistry is kept as simple as possible. It includes mechanism of action, structure activity relationships and mainly focus on the synthesis of selected compounds as per the course curriculum. The text is divided into five units, discussing a wide variety of topics and meet the requirements of the students. 1. Drugs Affecting Autonomous Nervous System 2. Drugs Affecting Central Nervous System-I 3. Drugs Affecting Central Nervous System-II 4. Drugs Affecting Central Nervous System-III 5. Autocoids