Zitat aus dem in #1 verlinkten Wiki-Artikel: (Ich finde die Geschichte dieses Stabs schon sehr interessant. Was wie eine moderne Zuckerstange aussieht, hat eine sehr lange Tradition.)
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. (and the twined pole motif is likely related to the Staff of Hermes, aka the Caduceus, evidenced for example by early physician van Helmont's of himself as "Francis Mercurius Van Helmont, A Philosopher by that one in whom are all things, A Wandering Hermite," op. cit., preface.)
At the Council of Tours in 1163, the clergy was banned from the practice of surgery. From then, physicians were clearly separated from the surgeons and barbers. Later, the role of the barbers was defined by the College de Saint-Côme et Saint-Damien, established by Jean Pitard in Paris circa 1210, as academic surgeons of the long robe and barber surgeons of the short robe.
In Renaissance-era Amsterdam, the surgeons used the colored stripes to indicate that they were prepared to bleed their patients (red), set bones or pull teeth (white), or give a shave if nothing more urgent was needed (blue).
[@Rava:] After the formation of the United Barber Surgeon's Company in England, a statute required the barber to use a red and white pole (Fettschrift von mir) and the surgeon to use a red pole. In France, surgeons used a red pole with a basin attached to identify their offices. Blue often appears on poles in the United States, possibly as a homage to its national colors. Another, more fanciful interpretation of these barber pole colors is that red represents arterial blood, blue is symbolic of venous blood, and white depicts the bandage.
In dem Artikel wird auch auf die in #23 erwähnte optische Täuschung eingegangen.