Technical Abstract: Six women (42.6±4.5 y; 82.7±15.5 kg BW) (randomly assigned) consumed either 0 or 1 cup/d of frozen BB for 2 weeks. On the last day of the treatment (Trt) period, participants came into a medical center and were given a breakfast drink [Control (C) or BB] corresponding to Trt consumed during period and blood was collected during the next 4 h. Following a 2 wk washout, participants were placed on the opposite Trt for 2 weeks and the appropriate meal given. The C and BB breakfast meal provided 478 Cal, 94.5 g carbohydrate, 5.4 g fat and 11.0 g protein. In the BB meal, calories, fat and protein were removed to account for that in the BB powder. The freeze dried BB powder was 20.3% of the drink and provided 1424 mg anthocyanins, 5046 mg phenolics, and 39.9 mmol Trolox Equivalents (TE) of ORAC. Whole blood ex vivo PA and ATP release (nmol) were determined at 0 (before meal) and at 4 h after the meal using collagen (1, 2 or 5 µg/mL)(COL) as an agonist. Platelet ATP release increased in subjects that consumed BB compared to C (p<0.001). Increasing COL concentrations increased ATP release (p<0.001), but the interaction of COL by Trt was not significant. PA increased with increasing COL (p<0.001), but was not affected by sampling time (0 vs 4 h). An interaction of Trt by COL (p<0.065) was observed in ex vivo PA with 1 µg/mL COL decreasing and higher COL increasing PA in BB subjects. Dietary BB may affect cardiovascular events involving PA.