Pharmacology is the study of drugs and their actions within the body. It deals with how drugs are absorbed, distributed, metabolized and excreted by the body, as well as their physiological effects. The document provides a brief historical overview of pharmacology and important discoveries. It discusses the development process for new drugs, which includes preclinical testing in animals followed by clinical trials in humans in four phases. Stringent regulations and guidelines govern the development and approval of new drugs to ensure safety and efficacy.