Faith healing is the practice of some religious and spiritual groups of choosing to pray for the recovery of the ill or injured. The term is most commonly associated with the practice of calling upon God to enact a miraculous cure when conventional medicine has no answer. An example would be a man in a wheelchair asked to rise who normally would have no ability to do so. Within Christianity, this practice is most common within the Charismatic movements.
Other groups have a more controversial doctrine. For instance Christian Scientists don't believe in illness, seeing it as a manifestation of a spiritual battle. There have been cases of deaths that have resulted where it is believed that modern medical care could have cured the condition. Christian Scientists report that their methods actually result in higher rates of positive results on average, although there are no formal studies that have been done that would be acceptable within the scientific community.
Occasionally religious practitioners will take it upon themselves to set their own standards and forego medical care while relying on prayer. This is frowned upon by most organized religious institutions. In at least one case this has led to criminal charges when a couple who had not gone to church in years chose this path. Their child died and it was determined that the death could have been prevented by modern medicine.
Faith healing and the Bible
Believers in faith healing believe that the following Bible passages support it:
And Asa in the thirty and ninth year of his reign was diseased in his feet, until his disease [was] exceeding [great]: yet in his disease he sought not to the LORD, but to the physicians. And Asa slept with his fathers, and died in the one and fortieth year of his reign. 2Chronicles 16:12-13 (KJV)
Is any sick among you? let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord: And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him. Confess [your] faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much. James 5:14-16 (KJV)