All aspects of stroke management are best considered within the World Health Organisation's framework of illness, which acknowledges four levels: pathology; impairment; disability, and handicap. Prevention ultimately aims to prevent death and minimise handicap. It may be targetted at pathology, preventing cerebral infarction; impairment, preventing symptoms and signs; disability, minimising dependence, or handicap, maximising freedom within society. The risk of recurrence of symptomatic stroke is relatively low (10%/year) and the reduction in risk achievable is only modest (20% reduction). Consequently, it is always necessary to balance the risks of intervention, and the costs (e.g. in terms of reduced pleasure or increased anxiety) against the potential benefit. In severely dependent people, it is unlikely that intervention is warranted.