This doctor successfully uses the power of placebo:

So that night, in a pretty loud voice, I asked the older nurse, “Now give me the magic towel”. She had no clue either, but she knew I needed an aperture drape, which is a sterile cloth sheet with a hole big enough to work through in its center. As she was unfolding it, I loudly and slowly explained to her that ‘this is the magic towel that makes boys with cuts fall asleep and not feel anything at all’. I think she got it, though the other two certainly didn’t. And why should they have? Even I didn’t think it would work-it just seemed like something my mom might try and it didn’t take any time or cost anything or seem to pose any danger. And the kid kept on screaming, harder and louder.

But then once the cloth touched his face, he turned off like a light. In fact, he turned off so fast and so completely that I got a little scared. But I could feel him breathing and his color was good, so I kept working. The younger nurse, however, started to pick up the drape-she was really scared. I tried to stop her without talking, without breaking the spell. In a mask all you can do is a kind of growl with your eyes.