BloodlettingMike Rappaport

The end of bloodletting:

Bloodletting was used routinely until 1836 when French physician Pierre Louis conducted one of the first clinical trials in medicine.  Louis compared pneumonia patients whom he treated with aggressive bloodletting and those he treated without it.  Louis found that bloodletting was linked to far more deaths. … George Washington, the first president of the United States, … died two days after a doctor treated his sore throat by draining almost five pints of blood.  … A remarkably high percentage of medical decisions still reflect the often-obsolete practices that a doctor learned in medical school, the ingrained traditions of a hospital or region.

This story really makes you appreciate empiricism.