Acupuncture is a very effective placebo (because you can really feel it working). There's a whole complex theory about points all over the body which affect ailments in different parts of the body, also based on personality type, but (of course!) none of it matters. Carefully poke someone with needles anywhere (and pretend there's some meaning behind the placement) and the effect is the same.

The big give-away that a treatment is just a convincing placebo is that it claims to help with everything.