When I asked my medical students to name famous doctors in the history of medicine, their first answer was Harold Shipman, the GP who murdered hundreds of patients.

I nearly swallowed my tongue.

Their second answer was House, the fictional doctor from the American TV series.

Tears of frustration welled up in my eyes.

Their third answer was Hippocrates, presumed author of the Hippocratic Oath - I breathed a sigh of relief.

Written nearly 2,500 years ago, the Oath is the most famous text in Western medicine, yet most people (including doctors) know precious little about it.

One GP recounted the story of an elderly patient who believed the Oath instructed doctors never to tell patients the truth. It contains no such advice.

Here is a brief guide to the Oath.

The Oath starts: "I swear by Apollo the physician and by Asclepius and Hygieia and Panacea... to bring the following oath to fulfilment."

Apollo, the god of healing, fell in love with a human, Coronis.

In his absence, Apollo sent a white crow to look after her.

When the crow informed Apollo that Coronis loved another man, Apollo's rage turned the crow black.

To avenge her brother, Apollo's sister shot Coronis with an arrow and, as she lay dying, Coronis told Apollo that she was bearing his child.

Although Apollo could not save Coronis, he rescued the unborn child, Asclepius.

Hygieia, the goddess of health, and Panacea, the goddess of cures, are the daughters of Asclepius.

According to legend, Hippocrates was a descendant of one of Asclepius' sons.

Inspiration

Doctors taking the Oath would doubtless have been inspired by this illustrious lineage of healers.

The next section instructs the doctor to treat his teachers as his parents, and to pass on the art of medicine to the next generation of healers.

The Oath continues: "And I will use treatments for the benefit of the ill in accordance with my ability and my judgment, but from what is to their harm and injustice I will keep them."

In other words, doctors should act in the best interests of their patients, and when unjust circumstances arise - for instance, a certain life-prolonging drug may not be available on the NHS - they should strive to correct the injustice harming their patients.

The next part seemingly concerns euthanasia or physician-assisted suicide, saying: "And I will not give a drug that is deadly to anyone if asked, nor will I suggest the way to such a counsel."

Two leading scholars of the Oath, Littre and Miles, have however suggested that this passage alludes to the then common practice of using doctors as skilled political assassins.

Steven Miles notes: "Fear of the physician-poisoner may be traced very close to the time of the Oath."

The word "euthanasia" (meaning "easeful death") was only coined a century after the writing of the Oath.

Abortion

The text continues: "And likewise I will not give a woman a destructive pessary."

This passage is often interpreted as a rejection of abortion.

However, abortion was legal at the time and the text only mentions pessaries (a soaked piece of wool inserted in the vagina to induce abortion), not the oral methods of abortion also used in ancient Greece.

As pessaries could cause lethal infections, the author of the Oath may have had a clinical objection to the method, rather than a moral objection to abortion itself.

The next sentence - "In a pure and holy way, I will guard my life and my art and science" - is a call for professional integrity.

Doctors should refrain from immoral behaviour and resist the temptations that accompany their privileged position (today, from drug companies offering generous gifts, for example).

Surgery

The Oath continues: "I will not cut, and certainly not those suffering from stone, but I will cede this to men who are practitioners of this activity."

Another common misconception is that the Oath forbids surgery.

In fact, it instructs doctors to acknowledge the limits of their competence and to refer cases to more specialised practitioners.

Next, the doctor enters the patient's house: "Into as many houses as I may enter, I will go for the benefit of the ill, while being far from all voluntary and destructive injustice, especially from sexual acts both upon women's bodies and upon men's."

The need for such a statement reflects the wide distrust in healers at the time.

In a competitive marketplace where quacks abounded, it was necessary to reassure the public that doctors would not exploit patients.

Confidentiality

The penultimate section deals with confidentiality and reads: "And about whatever I may see or hear in treatment, or even without treatment, in the life of human beings, I will remain silent, holding such things to be unutterable."

As today, patients in ancient times shared deeply personal information with doctors on the assumption that their details would not be revealed to others.

Without this trust, patients may withhold facts that would help the doctor make an accurate diagnosis.

The text ends with the rewards that await those who respect the Oath ("the benefits both of life and of art and science, being held in good repute among all human beings for time eternal") and the punishment of those who do not ("if, however, I transgress and swear falsely, the opposite of these").

This whistle-stop tour of the Oath gives some idea of the content and spirit of this ancient text.

In an age of technological developments, cosmetic surgery, complementary medicine, drug companies, and many other temptations for patients and doctors alike, the spirit of the Oath is as relevant as ever.