Patient safety has been an under-recognised and under-researched concept until recently. It is now high on the healthcare quality agenda in many countries of the world including the UK. The recognition that human error is inevitable in a highly complex and technical field like medicine is a first step in promoting greater awareness of the importance of systems failure in the causation of accidents. Plane crashes are not usually caused by pilot error per se but by an amalgam of technical, environmental, organisational, social and communication factors which predispose to human error or worsen its consequences. In healthcare, the systematic investigation of error in the administration of medication will often reveal similarly complex causation. Experience and research from other sectors, in particular the airline industry, show that the impact of human error can be reduced if the necessary work is put in to detect and then remove weaknesses and vulnerabilties in the system. The NHS is putting in place a comprehensive programme to learn more effectively from adverse events and near misses. This aims to reduce the burden of the estimated 850,000 adverse events which occur in hospitals each year as well as targeting high risk areas such as medication error.