Aspirin has long been known to prevent strokes and heart attacks in patients with a previous stroke or heart attack.  But aspirin has potentially serious side-effects.  Aspirin can cause stomach ulcers, and it inhibits blood clotting raising the risk of life-threatening bleeding. If we knew in advance that a patient was going to be in a car accident or have a bleeding stomach ulcer, we would discontinue the aspirin a week before the event and minimize the bleeding risk.  (This is exactly what w...