The question whether prayer can heal illness has for years been the subject of speculation.
To once and for all obtain an answer to this issue, a scientifically rigorous investigation was designed, involving more than 1,800 patients:
At six hospitals, patients were monitored who received coronary bypass surgery, in which doctors reroute circulation around a clogged vein or artery. The patients were broken into three groups. Two were prayed for; the third was not. Half the patients who received the prayers were told that they were being prayed for; half were told that they might or might not receive prayers.
Members of the St. Paul’s Monastery; the Community of Teresian Carmelites and a Missouri prayer ministry were asked to deliver the prayers, using the patients’ first names and the first initials of their last names.
The congregations were told that they could pray in their own ways, but they were instructed to include the phrase, “for a successful surgery with a quick, healthy recovery and no complications.”

Published in the American Heart Journal, the researchers who run the study found no differences between those patients who were prayed for and those who were not when analyzing complications in the 30 days after the operations.
In addition, a significantly higher number of the patients who knew that they were being prayed for (59 percent) suffered complications, compared with 51 percent of those who were uncertain.

The new study was rigorously designed to obtain robust results but experts said the study could not overcome an important confounding factor: the unknown amount of prayer each person received from friends and families who pray daily for their loved ones.