['Statins reportedly have anti-inflammatory and anti-thrombotic effects aside from cholesterol-lowering. This study aimed to evaluate the effect of pre-existing statin use on platelet activation markers and clinical outcome in acute ischemic stroke patients.', 'This prospective study evaluated 172 patients with acute ischemic stroke divided in two groups: patients with pre-existing statin (n = 43) and without pre-existing statin (66 cases with statins initiated post-stroke and 63 without statin treatment). Platelet activation markers (CD62P and CD63) were measured by flow cytometry at different time points after stroke and analyzed with clinical outcome.', 'The CD62P and CD63 expressions on platelets were significantly lower in the patients with pre-existing statin use compared to the patients without pre-existing statin use on Day 1 post-stroke (p < 0.05). The CD62P expression was significantly lower in the patients with pre-existing statin use on 90 days after the acute stroke (p < 0.05). Patients with pre-existing statin use had lower incidences of early neurologic deterioration (END) than those without treatment (p < 0.05). Among several baseline clinical variables, admission NIHSS score, history of coronary artery disease, and pre-existing statin use were independent predictions of good clinical outcome at three months.'] Is statin pre-treatment associated with lower platelet activity and favorable outcome in patients with acute non-cardio-embolic ischemic stroke?