I remember seeing some sections in the Hippocratic Oath that caused me to raise my eyebrows. Most people are familiar with this part only:
I will use regimens for the benefit of the ill in conformity with my ability and judgment, but from what is to their hurt and injustice I will keep them.
This is the "do no harm" part.
But there's a couple other parts that I thought were very interesting - the gatekeeping of the profession, and the "we the doctors won't ever do any surgery". I assume the later was because of a reciprocal deal with the surgeons.
Here are the applicable parts:
To hold him who has taught me this art as equal to my parents and to live my life in partnership with him, and if he is in need of money to share mine with him, and to consider his offspring equal to my own brothers in male lineage and to teach them this art—if they desire to learn it—without fee and covenant; to give a share of precepts and oral instruction and all other learning to my sons and to the sons of him who has instructed me and to pupils who have signed the covenant and taken an oath according to the medical law, but to no one else.
So basically - teach to your sons, and your teachers sons...but no one else, no one who has not "signed the covenant". Medical knowledge should not be shared.
I will not use the knife, not even on sufferers from stone, but will withdraw in favor of such men as are engaged in this work.
Surgeons get to use the knife (to remove kidney stones, or do whatever) but doctors can't.