The red, white and blue barber's pole represents bloodletting. Bloodletting was a surgical ritual performed during an era when barbers offered versatility by performing both personal care and medical procedures.
The red in the pole represents blood, while the white represents the bandages used to care for the wound. While the red and white pole is prevalent in Europe, the blue is an addition in American barber poles, and may be symbolic of blue veins or patriotism.
The bloodletting procedure was once limited to clergymen until Pope Alexander III prohibited them from performing the ritual. Barbers then took over the procedure. Bloodletting was performed by barbers using a sharp razor. The patient would hold a stick to make the veins appear more prominent. This stick is thought to represent the barber's pole. The barber would then slice a vein and let it bleed. This procedure was thought to cure many ailments. Barbers were often consulted for the service of bloodletting due to their knowledge of shaving and access to sharp razors during a time when doctors were considered too busy to perform the administrative procedure.
In addition to bloodletting, people visited barbers for tooth pulling, broken bone settings, haircuts, and shaves. By the mid-1500s, barbers were no longer allowed to perform medical procedures due to fears of infection and better medical knowledge, but the red, white and blue poles remain a nostalgic symbol of the classic barber's shop.