In reply to TickleFinger:
As part of chiropractic (there's a whole other discussion) treatment for chronic back pain a few years back, the chiropractor suggested some acupuncture to 'release' some tightness and make manipulation easier.
She put the pins in and did the treatment there and then. My back felt better a few days later (as was often the case after these sessions) but where the pins had been in got inflamed and I suffered flu-like symptoms for about a week. This might have been coincidence, but you could say the same about people's positive experiences too (regression to mean etc).
I took away from the whole experience that both acupuncture and chiropractic treatment are of questionable efficacy (especially when it comes to long-term, root cause care). The best treatment I've found for my back problems has come from genuine physio, lifestyle changes and staying active.