Primum non nocere  

The Hippocratic Oath is one of the most widely known Greek medical texts and has been historically taken by physicians.  It is an agreement to adhere to ethical standards in the healing practices.  Through this day, these continue to be of paramount importance.

Some of the main principles are that of medical confidentiality.  This has become a medical rite of passage in many countries.  It includes the promise to first do no harm.

In Western culture, Hippocrates is considered the father of medicine.

You may read this law at:

http://www.bartleby.com/38/1/2.html

Alternatively, you may listen to this in an audiobook format here: