The barber pole as a symbol of the profession is a legacy of bloodletting. The barber surgeon's necessities for that curious custom were a staff for the patient to grasp (so the veins on the arm would stand out sharply), a basin to hold leeches and catch blood, and a copious supply of linen bandages. After the operation was completed, the bandages would be hung on the staff and sometimes placed outside as advertisement. Twirled by the wind, they would form a red white spiral pattern that was later adopted for painted poles. The earliest poles were surmounted by a leech basin, which in time was transformed into a ball.
One Interpretation of the colors of the barber pole was that Red represented the blood, Blue the veins, and White the bandages. Which has been retained by the modern Barber-Stylist.