Clinical Pharmacology is the medical specialty which studies the relationship between drugs and humans. It studies basic pharmacology which includes principles of pharmacokinetics, pharmacodynamics, and their clinical application. It studies drug research, including laboratory practice, drug development, evaluation of efficacy, safety, quality and cost effectiveness, and ethical aspects. It encompasses principles of rational prescribing, and the quality use of medicines (QUM) – principals which may conflict with other guarantees such as maintaining a viable pharmaceutical industry, safety and efficacy standards, and ‘equity of access’ to medicines. QUM involves the appropriate and safe use of medicines and seeks to improve patient outcomes. Some of the activities undertaken to support QUM include: analysis of statutory and regulatory processes, assessment and minimisation of adverse reactions and interactions, promotion of rational prescribing and education, contribution to drug treatment development and implementation, development of local and national drug lists, monitoring and evaluation of drug usage and therapies, promotion of cost-effective drug use, and involvement in further QUM research. This field of medicine plays an important role maintaining standards of therapeutic drug use by contributing to rational, evidence-based, and cost-effective prescribing. However, there are ongoing challenges in this field, such as incorporating advances in medical technology, integrating new knowledge, responding to changing legislative and funding requirements, reducing drug dependency, maintaining quality control, and managing the impact of pressures from the pharmaceutical industry and governmental groups on the quality of pharmacology practice.