The improvement topic series is a set of briefing papers about areas of quality and safety which general practice clusters could usefully focus improvement activity on. They summarise research, guideline and other evidence about areas of care which can be improved, and improvement methods and interventions. Multimorbidity and inappropriate polypharmacy impact patient care, with consequences of drug-drug interactions and adverse drug events, drug-related hospitalisations, non-adherence and higher health care costs. Decisions on starting and stopping medicines in older people are complex due to a number of factors including the plethora of single disease guidelines which are based on evidence from research that largely excludes most people with multimorbidity. This paper describes measures and improvement methods being implemented in the real-world in Scottish general practice.