The incidence of stroke on cranial computed tomography (CT) and change in echocardiographic vegetation area was prospectively compared in a preliminary observational study involving nine patients with infective endocarditis randomized to either low‐dose aspirin (75 mg d^‐1, Group I, n = 4) or no aspirin (Group II, n = 5). Two symptomatic cerebral infarcts and one myocardial infarct occurred in the controls, compared to no events in patients on aspirin during a total observation period of 343 d (range 28–49 d). The mean vegetation area decreased in the aspirin group (mean change = ‐0.24 cm²), compared to an increase in controls (mean change = ± 0.35 cm²). The platelet half‐life (normal range 5–6 d), which was measured using Indium‐111 radiolabelling, tended to be lower in Group II (4.6 ± 0.2 vs. 3.9 ± 0.5 d). No side‐effects or complications attributable to aspirin were observed. A possible role for adjunctive aspirin therapy in the prevention of embolic complications in infective endocarditis is suggested, and warrants further study.