Wandering through a back street in Rayleigh on my way to pick up my new glasses this morning, I spotted an old remnant of days gone by. This trade sign is widely recognized as a barber pole, and dates back to the Middle Ages. According to Wikipedia, its history is a rather gory one:
The origin of the red and white barber pole is associated with the service of bloodletting and was historically a representation of bloody bandages wrapped around a pole. During medieval times, barbers performed surgery on customers, as well as tooth extractions. The original pole had a brass wash basin at the top (representing the vessel in which leeches were kept) and bottom (representing the basin that received the blood). The pole itself represents the staff that the patient gripped during the procedure to encourage blood flow.
More than you wanted to know?