Charaka Samhita contains an Anushasana - the Atreya Anushasana (seventh century BC) - predating the famous Hippocratic Oath by two centuries. This oath bears testimony to the high level of professional ethics in ancient India.
1) The teacher then should instruct the disciple in the presence of the sacred fire,Brahmanas(Brahmins) and physicians.
2) (saying)"Thou shalt lead the life of a celibate, grow thy hair and beard, speak only the truth,eat no meat,eat only pure articles of food, be free from envy and carry no arms.
3) There shall be nothing that thou should not do at my behest except hating the king,causing another's death, or committing an act of great unrighteousness or acts leading to calamity.
4) Thou shalt dedicate thyself to me and regard me as they chief. Thou shalt be subject to me and conduct thyself for ever for my welfare and pleasure. Thou shalt serve and dwell with me like a son or a slave or a supplicant. Thou shalt behave and act without arrogance, with care and attention and with undistracted mind, humility, constant reflection and ungrudging obedience. Acting either at my behest or otherwise, though shalt conduct thyself for the achievement of thy teacher's purpose alone, to the best of thy abilities.
5) If thou desirest sucess, wealth and fame as a physician and heaven after death, thou shalt pray for the welfare of all creatures beginning with the cows and Brahmanas.
6) Day and night, however thou mayestbe engaged, thou shalt endeavor for the relief of patients with all thy heart and soul. Thou shalt not desert or injure thy patient for the sake of thy life or thy living. Thou shalt not commit adultery even in thought. Even so, thou shalt not covert other's possessions. Thou shalt be modest in thy attire and appearance. Thou shouldst not be a drunkard or a sinful man nor shouldst thou associate with the abettors of crimes. Thou shouldst speak words that are gentle, pure and righteous, pleasing, worthy, true, wholesome, and moderate. Thy behaviour must be in consideration of time and place and heedful of past experience. Thou shalt act always with a a view to the acquistion of knowledge and fullness of equipment.
7) No person,who are hated by the king or who are haters of the king or who are hated by the public or who are haters of the public, shall recieve treatment. Similarly, those who are extremely abnormal, wicked, and of miserable character and conduct, those who have not vindicated their honor, those who are on the point of death, and similarly women who are unattended by their husbands or guardians shall not receive treatment.
8) No offering of presents by a women without the behest of her husband or guardian shall be accepted by thee. While entering the patient's house, thou shalt be accompanied by a man who is known to the patient and who has his permission to enter; and thou shalt be well-clad, bent of head, self-possessed, and conduct thyself only after repeated consideration. Thou shalt thus properly make thy entry. Having entered, thy speech, mind, intellect and senses shall be entirely devoted to no other thought than that of being helpful to the patient and of things concerning only him. The peculiar customs of the patient's household shall not be made public. Even knowing that the patient's span of life has come to its close, it shall not be mentioned by thee there, where if so done, it would cause shock to the patient or to others. Though possessed of knowledge one should not boast very much of one's knowledge. Most people are offended by the boastfulness of even those who are otherwise good and authoritative.
9) There is no limit at all to the Science of Life, Medicine. So thou shouldst apply thyself to it with diligence. This is how thou shouldst act. Also thou shouldst learn the skill of practice from another without carping. The entire world is the teacher to the intelligent an the foe to the unintelligent. Hence, knowing this well, thou shouldst listen and act according to the words of instruction of even an unfriendly person, when his words are worthy and of a kind as to bring to you fame, long life, strength and prosperity.
10) Thereafter the teacher should say this - "Thou shouldst conduct thyself properly with the gods, sacred fire, Brahmanas, the guru, the aged, the scholars and preceptors. If thou has conducted thyself well with them, the precious stones, the grains and the gods become well disposed towards thee. If thou shouldst conduct thyself otherwise, they become unfavorable to thee.” To the teacher that has spoken thus, the disciple should say, "Amen."
(from: Reich WT (ed.) Encyclopedia of Bioethics, revised edition Vol 5. Simon & Schuster MacMillan, New York, 1995)