Here's what the
Adverse effects of spinal manipulation: A systematic review study (which was published in this month’s Journal of the Royal Society of Medicine) has to say about that:
Quote:
The effectiveness of spinal manipulation for most indications is less than convincing.5 A risk-benefit evaluation is therefore unlikely to generate positive results: with uncertain effectiveness and finite risks, the balance cannot be positive.
-snip-
It is, of course, important to present any risk-benefit assessment fairly and in the context of similar evaluations of alternative therapeutic options. One such option is drug therapy. The drugs in question—non-steroidal anti-inflammatory drugs (NSAIDs)—cause considerable problems, for example gastrointestinal and cardiovascular complications.72,73 Thus spinal manipulation could be preferable to drug therapy. But there are problems with this line of argument: the efficacy of NSAIDs is undoubted but that of spinal manipulation is not, and moreover, the adverse effects of NSAIDs are subject to post-marketing surveillance while those of spinal manipulation are not. Thus we are certain about the risks and benefits of the former and uncertain about those of the latter. Finally, it should be mentioned that other therapeutic options (e.g. exercise therapy or massage) have not been associated with significant risks at all.
Ernst, E. Adverse effects of spinal manipulation: A systematic review. J R Soc Med 2007; 100:06-0100.1-9
http://www.jrsm.org/cgi/content/full/100/7/330
[My bold and underscoring]