Cytochrome P450 is a hemeprotein which plays an important role in the metabolism of drugs and other xenobiotics. Drug metabolism is the metabolic breakdown of drugs by living organisms, usually through specialized enzymatic systems. There are generally three phases for metabolism of xenobiotics, which include modification, conjugation, and excretion. The metabolism of drugs occurs at numerous locations in the body including the liver, lungs, kidneys, intestinal wall, and plasma. The liver is the main site of drug metabolism that facilitates and detoxifies the excretion of compounds that could be harmful to the organism. This mechanism works by enzymatically converting the lipid-soluble compounds to more water-soluble compounds. Cytochrome P450 enzyme is imperative for hormone breakdown and synthesis and it functions to metabolize drugs and endogenous metabolism products like bilirubin. This book outlines the role of Cytochrome P450 in disease and drug metabolism. It aims to shed light on some of the unexplored aspects of this enzyme and recent research in this field. Students, researchers, experts, and all associated with pharmaceutical sciences will benefit alike from this book.