Buddha of Medicine
Buddha of Medicine (Skt. Bhaiṣajyagurubuddha; Tib. Sangyé Menla; Wyl. sangs rgyas sman bla) is an important buddha in the Mahayana tradition, whose main initial vow as a bodhisattva was to become able to completely free all sentient beings from their illnesses. In Tibetan Buddhism, he is central to the Four Medical Tantras, which are the basis of Tibetan medicine, and to many sadhanas of healing.
When the Buddha of Medicine appears as a deity in sadhanas of healing, because deities are a means of communication, the form or appearance of each deity reflects the different activities which they embody and in which they engage, and are determined by the aspirations they made at the time of their initial generation of bodhichitta.
In the case of the Buddha of Medicine there is a specific set of twelve aspirations that relate to his primary motivation to remove the physical and mental suffering of beings in general, but primarily mental and physical illness caused through imbalance of the elements. 
- Thrangu Rinpoche, Medicine Buddha Teachings, Snow Lion Publications ISBN 1-55939-216-9, pages 105-117.
- Derge Kangyur, vol.87, ff.274r-283v., Wyl. phags pa bcom ldan 'das sman gyi bla bai DUR+Ya'i 'od kyi sngon gyi smon lam gyi khyad par rgyas pa zhes bya ba theg pa chen po'i mdo.
- Tulku Thondup, Boundless Healing (Shambhala: Boston, 2001), Part Three, Chapter Eight: 'Meditation on the Healing Buddha', pages 131-171