"Systematic reviews of controlled clinical studies of treatments used by chiropractors have found no evidence that chiropractic manipulation is effective, with the possible exception of treatment for back pain.[8] A 2011 critical evaluation of 45 systematic reviews concluded that the data included in the study "fail[ed] to demonstrate convincingly that spinal manipulation is an effective intervention for any condition."[10] Spinal manipulation may be cost-effective for sub-acute or chronic low back pain, but the results for acute low back pain were insufficient.[11] No compelling evidence exists to indicate that maintenance chiropractic care adequately prevents symptoms or diseases.[12]"
I was under the impression that the assertion that chiropractic neck manipulation causes vertebral artery dissection is often suggested, but that evidence of such a causation is inconclusive. I certainly believe it, but I can't assume. Chiropractors may twist the inconclusiveness into suggesting that such neck manipulation is safe, but that's a fallacy.
I lean towards believing it, based on having met a person who suffered a vertebral artery dissection, and cerebellar infarcts, following chiropractic treatment.