Om Namo Bhagavate Bhekhandzye
Granting your request, from the heart and holy body of the King of Medicine, Guru Medicine Buddha, infinite rays of white light pour down completely filling your body from head to toe. They purify all your diseases and afflictions due to spirits and their causes, all your negative karma and mental obscurations. In the nature of light, your body becomes as clean and clear as crystal. The light rays pour down twice more, each time filling your body with blissful clean clear light which you absorb. You are thereby transformed into the holy body of Guru Medicine Buddha. At your heart appears a lotus and moon disk. Standing at the center of the moon disk, is the blue seed-syllable OM surrounded by the syllables of the mantra. As you recite the mantra, visualize rays of light radiating out in all directions from the syllable at your heart. The light rays pervade the sentient beings of all six realms. Through your great love wishing them to have happiness, and through your great compassion wishing them to be free from all sufferings, they are purified of all diseases and afflictions due to spirits and their causes, all their negative karma and mental obscurations.
medicine buddha mantra
Excerpt from 2000 edition of "Medicine Buddha Sadhana." Translated by Lama Thubten Zopa Rinpoche. See also this short form version.