A brief background of Medicine Buddha (Sangye Menla)

Bhaiṣajyaguru is described in the eponymous Bhaiṣajya-guru-vaiḍūrya-prabhā-rāja Sūtra, commonly called the Medicine Buddha Sutra, as a bodhisattva who made twelve (12) great vows. On achieving Buddhahood, he became the Buddha of the eastern pure land of Vaiḍūryanirbhāsa “Pure Lapis Lazuli”. There, he is attended to by two bodhisattvas symbolizing the light of the sun and the light of the moon respectively: 

• Sūryaprabha  
• Candraprabha 

A Sanskrit manuscript of the Bhaiṣajya-guru-vaiḍūrya-prabhā-rāja Sūtra was among the texts attesting to the popularity of Bhaiṣajyaguru in the ancient northwest Indian kingdom of Gandhāra. 

The twelve vows of Medicine Buddha upon attaining Enlightenment, according to the Medicine Buddha Sutra are:

1. I vow that my body shall shine as beams of brilliant light on this infinite and boundless world, showering on all beings, getting rid of their ignorance and worries with my teachings. May all beings be like me, with a perfect status and character, upright mind and soul, and finally attaining enlightenment like the Buddha.
2. I vow that my body be like crystal, pure and flawless, radiating rays of splendid light to every corner, brightening up and enlightening all beings with wisdom. With the blessings of compassion, may all beings strengthen their spiritual power and physical energy, so that they could fulfill their dreams on the right track.
3. I vow that I shall grant by means of boundless wisdom, all beings with the inexhaustible things that they require, and relieving them from all pains and guilt resulting from materialistic desires. Although clothing, food, accommodation and transport are essentials, it should be utilized wisely as well. Besides self-consumption, the remaining should be generously shared with the community so that all could live harmoniously together.
4. I vow to lead those who have gone astray back to the path of righteousness. Let them be corrected and returned to the Buddha way for enlightenment.
5. I vow that I shall enable all sentient beings to observe precepts for spiritual purity and moral conduct. Should there be any relapse or violation, they shall be guided by repentance. Provided they sincerely regret their wrong-doings, and vow for a change with constant prayers and strong faith in the Buddha, they could receive the rays of forgiveness, recover their lost moral and purity.
6. I vow that all beings who are physically disabled or sick in all aspects be blessed with good health, both physically and mentally. All who pay homage to Buddha faithfully will be blessed.
7. I vow to relieve all pain and poverty of the very sick and poor. The sick be cured, the helpless be helped, the poor be assisted.
8. I vow to help women who are undergoing sufferings and tortures and seeking for transformation into men. By hearing my name, paying homage and praying, their wishes would be granted and ultimately attain Buddhahood.
9. I vow to free all beings from evil thought and its control. I shall lead them onto the path of light through inculcating them with righteousness and honour so that they will walk the Buddha way.
10. I vow to save prisoners who have genuinely repented and victims of natural disasters. My supreme powers will bless those who are sincere and be freed from sufferings.
11. I vow to save those who suffer from starvation and those who committed a crime to obtain food. If they hear my name and faithfully cherish it, I shall lead them to the advantages of Dharma and favour them with the best food that they may eventually lead a tranquil and happy life.
12. I vow to save those who suffer from poverty, tormented by mosquitoes and wasps day and night. If they come across my name, cherish it with sincerity and practice dharma to strengthen their merits, they will be able to achieve their wishes.

If you pray to Medicine Buddha, you will quickly accomplish all that you wish. Just hearing the holy name of Medicine Buddha and the sound of his mantra closes the door to rebirth in the suffering lower realms. Therefore, at the time of death, it is excellent to recite both Tathagata Medicine Buddha’s holy name and his mantra in the ear of the dying person. It can cause someone who has been reborn in the suffering lower realms to immediately pass away and be reborn in a pure realm or amongst happy transmigrators. At the very least, it will shorten the duration of their suffering in the lower realms. It is excellent if this is done with bodhichitta, renouncing self and cherishing others.