I vote BS. One of the problems is that it is hard to do double-blind studies as it is difficult to give the patients a placebo when the treatment is sticking needles into your body. In fact, one term I've seen applied to it is that it is a "theatrical placebo".
When you read the underlying "logic" behind how acupuncture is supposed to work, it is obvious that it is a scam. "Qi" and "meridians"? Really?
