Fig. 1. Time course of whole blood platelet aggregation. Inducers: 2.5 μm adenosine diphosphate (ADP) (  A ), 1 μg/ml collagen (  B ), or 400 μm arachidonic acid (  C ). Treatments: single dose of aspirin (100 mg) or  S (+)-ibuprofen (dexibuprofen, 400 mg). Sample: healthy volunteers (n = 12). Each  point is mean ± SD of the data. *  P < 0.05 with respect to the aspirin value.