namo bhagavate bhaiṣajya-guru-vaiḍūrya-prabhā-rājāya | tathāgatāya-arhate samyak-saṁbuddhāya | tad-yathā oṁ bhaiṣajye bhaiṣajye bhaiṣajya-samudgate svāhā* ||
*This mantra is based on the Sūtra of the Original Vows of Seven Medicine Buddhas (Chinese Canon, Text 451). The popular Tibetan version differs in its last phrase, which is given below for your comparison.
tad-yathā oṁ bhaiṣajye bhaiṣajye mahā-bhaiṣajye rāja samudgate svāhā ||
Tibetans and Chinese have been reciting their respective versions of this mantra for centuries. Their testimonies provide evidence for the healing power of this mantra in both versions.