I am hoping that you get several responses to your question......
Reiki is a holistic "healing method" using the power of Universal Energy, ie -- God. It does not pretend to replace physical medical practices, but works in partnership with it.
I'm not sure how to "prove" that it works except that people that experience it report their responses to it.
I hope you get lots of responses because there are a number of people on this board who would be better qualified to answer than me........I'm definitely a novice!
Maryann