The Hippocratic Oath:

I swear by Apollo, the healer, Asclepius, Hygieia, and Panacea, and I take to
witness all the gods, all the goddesses, to keep according to my ability and my
judgment, the following Oath and agreement:

To consider dear to me, as my parents, him who taught me this art; to live in
common with him and, if necessary, to share my goods with him; To look upon his
children as my own brothers, to teach them this art.

I will prescribe regimens for the good of my patients according to my ability
and my judgment and never do harm to anyone.

I will not give a lethal drug to anyone if I am asked, nor will I advise such a
plan; and similarly I will not give a woman a pessary to cause an abortion.

But I will preserve the purity of my life and my arts.

I will not cut for stone, even for patients in whom the disease is manifest; I
will leave this operation to be performed by practitioners, specialists in this
art.

In every house where I come I will enter only for the good of my patients,
keeping myself far from all intentional ill-doing and all seduction and
especially from the pleasures of love with women or with men, be they free or
slaves.

All that may come to my knowledge in the exercise of my profession or in daily
commerce with men, which ought not to be spread abroad, I will keep secret and
will never reveal.

If I keep this oath faithfully, may I enjoy my life and practice my art,
respected by all men and in all times; but if I swerve from it or violate it,
may the reverse be my lot.

For other versions: http://en.wikipedia.org/wiki/Hippocratic_Oath