This document discusses rational drug use and provides guidelines for promoting it. It defines rational drug use as using the right drug, for the right patient, at the right time, dose, route and cost. Irrational drug use can occur through under-prescribing, incorrect prescribing, extravagant prescribing, over-prescribing and multiple prescribing. Promoting rational drug use involves teaching pharmacology and therapeutics, using essential drug lists, providing drug information to physicians and the public, and monitoring prescribing practices through drug use studies. Key components are patient and prescriber education, guidelines, regulations and ensuring drug supply systems support rational use.