Omacor (omega-3 fatty acid ethyl esters) is approved for treatment of severe hypertriglyceridemia, and may soon be approved for the treatment of moderate hypertriglyceridemia in combination with statins. In other words, the use of Omacor will continue to expand. The package insert notes that physicians should be attuned to the possibility of increased bleeding tendencies with high dose (4 g/d) Omacor use despite the fact that clinically significant bleeding has virtually never been reported with this dose (or even up to 7 g of EPA+DHA) in studies in patients on concomitant anti-platelet therapy undergoing highly invasive vascular procedures (e.g., diagnostic catheterization, angioplasty, coronary artery bypass grafting). Nevertheless, because omega-3 fatty acids are known to inhibit platelet function and to increase bleeding times(1), it is prudent to explore and carefully define the effects of this dose of Omacor on platelet composition and function.