Early History

• From ancient times up until the late 19th century, medicine based its diagnoses and treatments on the four body "humors": blood, phlegm, yellow and black bile. Back then, phlebotomy involved bloodletting to purge the disease from the body.
  
  

The Barber Pole

• In addition to surgeons, barbers used to practice bloodletting. The red and white barber pole was an advertisement for such services. The red stood for blood and the white signified a tourniquet, while the pole itself represented a stick the patient was made to squeeze.
  
  

Misconceptions

• By the end of the 19th century, bloodletting was debunked as useless. Patients easily fainted from having too much blood drained, did not recover from their illness and sometimes died as a result of the practice.
  
  

Modern Times

• Since the late 19th century, phlebotomy has meant the practice of drawing blood for laboratory testing and transfusion. You must be properly trained in the practice, typically at least as a licensed practical nurse, to be allowed to draw blood.