Researchers predict that the medicines of the future may not only look and work differently than those taken today, but tomorrow’s medicines will be tailored to genes. In 10 to 20 years, many scientists expect that genetics —the study of how genes influence actions, appearance, and health—will pervade medical treatment. Today, doctors usually give an “average” dose of a medicine based on body size and age. In contrast, future medicines may match the chemical needs of the body, as influenced by genes. Knowing the individual's unique genetic make-up could help doctors prescribe the right medicine in the right amount, to boost its effectiveness and minimize possible side effects. Along with these so-called pharmacogenetic approaches, many other research directions will help guide the prescribing of medicines. The science of pharmacology—understanding the basics of how our bodies react to medicines and how medicines affect our bodies—is already a vital part of 21st-century research. Chapter 1, “ABCs of Pharmacology,” tracks a medicine’s journey through the body and describes different avenues of pharmacology research today. Chapter 2 looks at how the body can heal itself and how it interacts with pharmaceuticals. Chapter 3 takes the reader through a journey of how medicines were made from nature and the processes which changed the composition from then to now. Finally chapter 4 provides an analysis of the challenges associated with producing medicines with the least impact on molecules.