Low-dose aspirin prophylaxis, 75–150 mg per day, reduces the risk of vascular events and there is also promising evidence that it may also reduce the risk of cancer. Increased use of aspirin may confer considerable benefits to the population, but the risk of causing a gastric bleed is certainly a major concern. There are ethical considerations related to the potential increased use of aspirin in the population. These include the balance of benefit and risk of the medicine, possible undesirable effects such as ‘risk compensation’ and ‘iatrogenesis’, as well as a potential impact on health inequalities. More research is therefore needed on aspirin, particularly to define and describe the population use of the drug. More evidence on aspirin, including an ongoing randomised controlled trial on vascular events, will allow appropriate policy responses to be made.