Rational drug use, definition of rational drug use, objectives of rational drug use, essential drug concept, definition of essential drugs, reasons for irrational use of drugs, hazards of irrational use of drugs, methods for development of RDU, role of pharmacist in rational drug use, steps to improve rational drug prescribi9ing, guidelines for rational prescribing of drugs, WHO interventions for rational prescribing of drugs, rational use of antibiotics, rational use of injections, rational use of common OTC drugs, examples of essential drugs, role of pharmacist in essential drug concept