Healing

And if at one time, through the care of an able physician, a member of that body was healed, the rest remained afflicted as before.

Bahá’u’lláh, Epistle to the Son of the Wolf, p. 60

Do not neglect medical treatment when it is necessary, but leave it off when health has been restored. Treat disease through diet, by preference, refrain from the use of drugs; and if you find what is required in a single herb, do not resort to a compounded medicament...Abstain from drugs when health is good, but administer them when necessary.

Bahá’u’lláh, Bahá’u’lláh and the New Era, p. 106

Thou hast written concerning the Tablet of Baka Ya Ali -- Baka Ya Vafi (Tablet of Protection). This Tablet is for the healing of ailments. Whenever one is anxious about the recovery of an ill one, he may read this prayer with a melodious voice while in a state of the utmost attention and concentration. (‘Abdu’l-Bahá, Tablets of ‘Abdu’l-Bahá v2, p. 469)

"In His Name, the Exalted, the All-Highest, the Most Sublime! Glorified art Thou, O Lord my God! O Thou Who art my God, and my Master, and my Lord, and my Support, and my Hope, and my Refuge, and my Light. I ask of Thee, by Thine Hidden and Treasured Name, that none knoweth save Thine own Self, to protect the bearer of this Tablet from every calamity and pestilence, and from every wicked man and woman; from the evil of the evil-doers, and from the scheming of the unbelievers. Preserve him, moreover, O my God, from every pain and vexation, O Thou Who holdest in Thy hand the empire of all things. Thou, truly, art powerful over all things. Thou doest as Thou willest, and ordainest as Thou pleasest. O Thou King of Kings! O Thou kind Lord! O Thou Source of ancient bounty, of grace, of generosity and bestowal! O Thou Healer of sicknesses! O Thou Sufficer of needs! O Thou Light of Light! O Thou Light above all Lights! O Thou Revealer of every Manifestation! O Thou the Compassionate! O Thou the Merciful! Do Thou have mercy upon the bearer of this Tablet, through Thy most great mercy and Thine abundant grace, O Thou the Gracious, Thou the Bounteous. Guard him, moreover, through Thy protection, from whatsoever his heart and mind may find repugnant. Of those endued with power, Thou, verily, art the most powerful. The Glory of God rest upon thee, O thou rising sun! Do thou testify unto that which God hath testified of His own Self, that there is none other God besides Him, the Almighty, the Best-Beloved.

Bahá’u’lláh, from a recently translated tablet from Arabic at the Bahá’í World Centre

Verily, I say, fasting is the supreme remedy and the most great healing for the disease of self and passion.

Bahá’u’lláh, The Importance of Obligatory Prayer and Fasting

At whatever time highly-skilled physicians shall have developed the healing of illnesses by means of foods, and shall make provision for simple foods, and shall prohibit humankind from living as slaves to their lustful appetites, it is certain that the incidence of chronic and diversified illnesses will abate, and the general health of all mankind will be much improved. This is destined to come about. In the same way, in the character, the conduct and the manners of men, universal modifications will be made.

‘Abdu’l-Bahá: Selections from the Writings of ‘Abdu’l-Bahá, p. 155

Different maladies occur which each have a special remedy. The skillful physician does not give the same medicine to cure each disease and each malady, but he changes remedies and medicines according to the different necessities of the diseases and constitutions.

‘Abdu’l-Bahá. Some Answered Questions, p 108