Nine normal male subjects were fed a reference diet typical of that consumed in the United States and a diet containing approximately 450 g salmon (salmon-rich diet). The salmon diet contained approximately 6 g omega 3 fatty acids that comprised 2.0% energy intake/d for each individual. The percent energy contribution of protein, carbohydrate, and fat (19%, 56%, and 25%, respectively) was identical for the two diets. Urinary excretion of 2,3-dinor-thromboxane B2 was significantly lower (0.74 +/- 0.26 ng/24 h) with the salmon diet compared with the reference diet (0.95 +/- 0.31 ng/24 h). In addition, in vitro generation of thromboxane B2 in response to collagen-stimulated aggregation of platelet-rich plasma from subjects consuming the salmon diet was reduced (1.87 +/- 0.79 ng/mL) compared with subjects consuming the reference diet (3.10 +/- 1.81 ng/mL). Urinary 2,3-dinor-6-oxo-prostaglandin F1 alpha excretion in subjects was not significantly different between the salmon diet (0.69 +/- 0.33 ng/24 h) and the reference diet (0.81 +/- 0.44 ng/24 h).