The Physician, or Doctor, trained at University for 7 years, and even before taking his medical degree, was expected to have a good grounding in the arts; he would have been both technician and philosopher.

He was the choice of the rich. He had to be paid, and paid well.
Snobbery of the day meant the more you paid - even having your pills covered in gold leaf - the better the treatment you believed you were getting!

Throughout this period most illnesses were blamed on an imbalance of the four "humours", wet, dry, hot and cold.
Of course illness was also thought to be divine retribution for wrong doing.

Methods of diagnosis included inspection of the patients urine - he or she need not even be present for this, a servant may deliver a specimen in a "jordan" - the look, the smell, and even the taste of it, supposedly giving clues as to the patients' problem.
A horoscope may also be drawn up. The "heavenly bodies" influencing different parts of the body e.g. Aries, the head; Taurus, the throat, etc.

Whatever the diagnoses, purging the patient in one form or another was generally prescribed. Bloodletting being a popular form, with "cupping" or leeches used for the elderly, the young or very sick.

A Physician would have your medicine prepared for you by the Apothecary.

A great deal of the medical knowledge the barber/surgeon had came from autopsies and embalming.

During a war the barber/surgeon would tend the wounds inflicted on the battlefield. Performing amputations and other duties including searching wounds with irons and other instruments, staunching blood flow, sewing flesh, setting bones, and even cutting the skull with iron tools.

In peacetime he would earn a living cutting hair and doing dentistry, possibly moving from town to town. He would still perform blood letting, lancing boils and burning out canker.

Although on the battlefield surgical procedures would have been carried out with the patient conscious, and without anaesthetic or pain relief, in peacetime help was given to those about to be treated.
  Seed of white henbane (a very poisonous plant) in wine; or a sleeping ointment used on the temples, armpits, hands and feet made from the juice of henbane, mandrake, hemlock (all poisonous), lettuce, poppy, with all their seeds crushed, and put into swine grease and boiled!
  You hoped he'd listened to his teacher very carefully!