Sangye Menla  or 

The mantra, or even the name of the Medicine Buddha (Skt: Bhaisajyaguru, Tib: Sangye Menla, Chin: Yaoshi-fo, Jap:Yakushi) is beneficial.   

Ven. Thrangu Rinpoche has said that a mantra is essentially an elaboration on the deity's name, and that any mantra is essentially the shortest possible form of the sadhana.  The mantra of Medicine Buddha is:

Tayatha, Om, bekandzeh, bekandzeh maha-bekandzeh, radza samungateh. Soha

'May all beings benefit from the sublime love and power of Sangye Menla' is often given as the meaning but it is not a literal translation.

Since the practice of Sangye Menla is considered a sutrayana practice (the Buddhist way as based mainly on scripture) no empowerment is necessary, but it is good to attend one or to ask for one when you have an opportunity. 

Khenpo Karthar has said that the practice of Sangye Menla also has been found beneficial in cases of mental illness.  And it is said that even hearing the name Sangye Menla only once has benefits for subsequent rebirth, as the Medicine Buddha has made 12 vows that describe the various ways and means he can use to help sentient beings with their sufferings.  

As red Amitabha is the Buddha of the Western Pure Land, blue Medicine Buddha is often considered the Buddha of the Eastern Pure Land.  His color is lapis lazuli blue. That dark blue, gold-threaded stone called lapis for short -- lapis is Latin for stone -- has been associated with healing at least since the time of Sumerian goddess (Mt. Sumeru = Meru) Inanna (Ishtar) who descended to the Land of the Dead to revive her brother/lover and then, returned.  Interestingly, ashi-  is the Sumerian root for heal; in Tibetan amchi is a healer.

Notice that the Buddha is not teaching in this image.  He is holding in his lap, a bowl of lapis lazuli [In Japan, the bowl is said to be of iron] in which is an arura or myrobalan plum.  His right hand displays a spray of arura.