It's not hard to find claims like these in the media or on the web from time to time.

Is there any scientifically verifiable evidence that prayer (in addition to appropriate medical/surgical treatment) has a benefit for a patient? Please keep answers to demonstrable evidence, such as:

  • Do prayed-for patients heal faster after surgery?

  • Do they have lower rates of post-operative infection?

  • Do they statistically demonstrate better outcomes?

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    There's a fairly readable discussion of evidence on Peter Norvig's site. He goes through a long list of papers, and finds that the ones that suggest prayer works had serious methodological flaws. (Arguably, this could have been due to looking harder for flaws in the papers with the conclusion Norvig disagreed with, but the flaws he found do seem major.) Apr 6, 2011 at 2:21

2 Answers 2


The American Heart Journal has published a three-year study of the therapeutic effects of intercessory prayer of 1800 patients undergoing heart bypass surgery.

The study divided subjects into three groups: those receiving no intercessory prayer, those that did, but didn’t know about it, and those that did and did know about it.

Its conclusion is very clear indeed:

Intercessory prayer itself had no effect on complication-free recovery from CABG, but certainty of receiving intercessory prayer was associated with a higher incidence of complications.

In other words: prayer doesn’t help. And if you know that you are prayed for, you do worse. Only slightly, but statistically significantly.

Scientific American has published a break-down of the study and its results.

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    @Konerak Well the question was explicitly about “prayed-for patients”, i.e. intercessory prayer. Apr 4, 2011 at 14:43
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    Excellent answer, I was about to cite the study myself.And before someone calls "BIAS!" on the study: It was funded by the (in)famous Templeton Foundation that doles out lots of money to scientists willing to say nice things about god.
    – Lagerbaer
    Apr 4, 2011 at 14:56
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    I see what you mean. Sorry, I'm not a native English speaker - from a logical point of view, a "prayed-for" patient does not include the prayer being the patient itself... after all, if you pray for yourself, are you not prayed-for? :)
    – Konerak
    Apr 5, 2011 at 10:16
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    @userunknown The study demonstrates that prayer, as implicitly defined by a lot of people (I’d claim that it’s the clear majority), and furthermore the only meaningful notion of prayer within the realm of empiricism, doesn’t work. Furthermore, as I’ve already said, I’ve answered the kind of question that’s on topic here. Any other kind of prayer is off-topic on skeptics.SE. I still don’t fully comprehend what exactly you don’t like about the answer. Apr 10, 2011 at 18:09
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    @KonradMorawski No, since the study was blinded. They praying people didn’t select who to pray for, and didn’t know their prognosis. Aug 29, 2012 at 18:25

I'm struggling to find links to actual scientific papers, but I am aware they exist and tend to show that if someone is prayed for and doesn't know it then there is no demonstrable increase in healing, but if someone is told that a group is praying for them they tend to heal quicker.

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    " but if someone is told that a group is praying for them they tend to heal quicker." I remember seeing a study which concluded exactly the opposite: when the "target" did not know on the prayer, it had no effect, when he knew about it, the healing was slower and there were more complications.
    – Suma
    Apr 4, 2011 at 8:42
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    Your argument as it stands is quite thin, wikipedia is not a great reference, and the godisimaginary link actually links to sites that better serve your argument (like the wired article). You'll have a lot more going for you if you can link to the specific study cited in the times online article, the one you mentioned (or anything published and peer-reviewed since Galton, and I know it's out there) or at least add where it can be found. Apr 4, 2011 at 8:45
  • @Suma Exactly right. I’m searching for the studies … Apr 4, 2011 at 9:30
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    The fact that the patient has to be informed someone is praying for them in order for it to work strongly suggests they're looking at placebo effect at best. I'd also theorize it depends heavily on the patient and their state of mind when they're informed of said prayer; not everyone would simply accept prayers in the spirit they're undoubtedly intended in... May 26, 2016 at 7:07

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