Bleeding, particularly within the gastrointestinal tract, is the only important side effect of low-dose aspirin therapy in patients that are not already known to be aspirin intolerant (e.g., allergy). Long term, low-dose aspirin therapy (i.e., 160 mg per day), is associated with about a two-fold increase in the risk of bleeding.15-17 This increase of bleeding is small in patients without known contraindications to aspirin. Evidences from randomized trials of aspirin in asymptomatic subjects, patients with vascular risk factors, or patients with a past history of vascular disease (more than 250,000 patient-years of follow-up), showed an absolute excess of major bleeding with aspirin from 0.3 to 1.7 episodes per 1000 patient-years, equivalent to an absolute risk of 1 event for every 1000 patients treated.15 Increasing doses of aspirin, even within the range of 100-300 mg per day, were associated with an increasing risk of gastrointestinal bleeding, with the lowest risk occurring in patients receiving 100 mg daily.15;18-19