I may be wrong on this, but aspirin comes from white willow bark, which is very high in antioxidants, so this helps prevent damage to your muscle tissue. Aspirin does thin your blood because it prevents platelets in your blood called prostaglandins from attaching to each other by attaching itself to them. These platelets are what clot a wound when you bleed, but aspirin prevents clotting to an extent, which is why you can not take aspirin 10 days prior to surgery. When the prostaglandins are attached to the aspirin, your blood is essentially thinner, which is why it supposedly helps prevent heart attacks and strokes, and with your blood being thinned i believe anything else you are taking, in this case ephedra, will circulate through your system faster, but this last point, i am not completely sure of.
