Defining polypharmacy according to numbers of medicines Tools to assess appropriateness of prescribing in polypharmacy Proposed pragmatic approach for identifying higher-risk polypharmacy 2 The epidemiology of polypharmacy Polypharmacy in primary care Polypharmacy in hospitals Medication use in care homes Polypharmacy in other countries Multi-morbidity and ageing as driving factors 3 Medicines optimisation and polypharmacy Evidence for improving medicines management in polypharmacy Reducing medication errors Polypharmacy and use of monitored dose systems Medication review and repeat prescribing Polypharmacy at discharge and medicines reconciliation Suggestions for improving care in the context of multi-morbidity Medicines management in care homes Polypharmacy and stopping medicines Medication waste, medicines management and polypharmacy 4 Evidence-based polypharmacy 5 Prescribing and polypharmacy in older people Are drugs for older people effective? Medication reviews, polypharmacy and older people