OBJECTIVES: The primary aim of the study was to determine societal utility scores for health states associated with events either benefiting from aspirin (myocardial infarction, stroke, angina) or potentially caused by aspirin (GI bleeding). The secondary aim was to determine the societal disutility score of taking aspirin every day. METHODS: Draft health states were developed based on a brief literature review and exploratory and validation interviews with cardiovascular (n=3) and stroke (n=2) specialists. The final health states were tested in a pilot study with members of the general public (n=6). In the main study, members of the general public (n=90 Canadians; n=86 Americans) completed a chained standard gamble (SG) interview, a Visual Analogue Scale (VAS) rating task (0-100), the EQ-5D and a  socio-demographic form. RESULTS: The samples were a reasonable match to the population of Canada and the US in terms of demographics (48% female, 67% white) and quality of life (rated by EQ-5D). Eight percent of participants had experienced one or more forms of CVD or stroke as described in the health states and 18% of participants were taking daily preventive aspirin. In patients who were not taking aspirin, adding daily aspirin to prevent CVD caused a decrement in utility of 0.018. Conversely, patients who were taking daily aspirin reported an increase in utility of 0.021 compared to if they were not taking aspirin. GI bleeding and transient ischemic attack were rated as the states with the highest utility (0.79) followed by angina (0.71 stable, 0.66 unstable). Various stages of MI and stroke were considered least desirable (0.10-0.63). CONCLUSIONS: The study highlights the benefit in utility that could be gained from preventing cardiovascular and stroke events. It also demonstrates that the minor burden of taking aspirin daily changes to a small incremental benefit in wellbeing in participants already taking aspirin.