Pharmacology is a biological discipline that is concerned with the study of a drug or medication action. A drug is a man-made, natural, or endogenous molecule that affects the cell, tissue, organ or organism, biochemically or physiologically. Pharmacology is the study of interactions between a living organism and chemicals that influence the normal and abnormal biochemical function. It blends the study of the drug composition and properties, synthesis and drug design, molecular and cellular mechanisms, molecular diagnostics, interactions, chemical biology and toxicology. Pharmacodynamics and pharmacokinetics are the two main branches of pharmacology that respectively study the effects of a drug on biological systems and the effects of biological systems on the drug. This book presents researches and studies performed by experts across the globe. Also included herein is a detailed explanation of the various concepts and applications of pharmacology. Those in search of information to further their knowledge will be greatly assisted by this book.