In reply
Hippocrates urged us, first, do no harm, but this should not be overinterpreted to accept no risks in making treatment decisions. Such a stance would leave us paralyzed as physicians because nearly every medical therapy and surgical intervention has a risk of complications. It is the calculus of the risk-benefit ratio that must be considered in making treatment decisions, and there has been a common misunderstanding of the math relevant to using tPA for stroke.