If chiropracty works, it would be a surprise given the history. See http://en.wikipedia.org/wiki/Chiropractic_history for more details, but basically it was founded by a complete crackpot and there's no reason to believe it should work.
Further, many studies have found weak effects, no effects, and negative effects. When you see this kind of evidential pattern, it almost always means that the effect isn't real and we're just seeing experimental error. See http://en.wikipedia.org/wiki/Chiropractic#Evidential_basis
That said, the placebo effect for something like chiropracty or massage can be very strong - and the placebo effect is real! Giving someone a saline shot creates a stronger effect than giving them a sugar pill; I don't know where chiropracty exists on that spectrum.
My own anecdotal experience would leave me surprised if controlled studies found that modern chiropractic care had no useful effect at all. Over a three month period I watched one guy go from a hunch-backed nerdy appearance to a shoulders-back, upright, and confident posture. Chiropractors probably can't cure ulcers, but they probably can accelerate improvements in posture, which have payoffs in other areas (improved posture->reduced pain->less stress caused by pain->better quality of life).
The article doesn't say it's locked, but I see no edit button.
I was trying to replace "Opinions differ as to the efficacy of chiropractic treatment" with "Opinions differ as to the ability of chiropractic treatment to produce an effect", because I have a grudge against overly complicated language.
Also, if you look to the top right corner of the page, there's a lock icon that shows the article is semi-protected. You can't edit it without logging in.
Further, many studies have found weak effects, no effects, and negative effects. When you see this kind of evidential pattern, it almost always means that the effect isn't real and we're just seeing experimental error. See http://en.wikipedia.org/wiki/Chiropractic#Evidential_basis
That said, the placebo effect for something like chiropracty or massage can be very strong - and the placebo effect is real! Giving someone a saline shot creates a stronger effect than giving them a sugar pill; I don't know where chiropracty exists on that spectrum.