We report the case of a 34-year-old man, treated by chiropractic manipulation for tension-type headache. The patient complained of a sharp occipital pain during the first session, followed by vomiting and loss of consciousness, and remained comatose for five days. Neurological examination detected persistence of dysarthria, ataxia, with delayed responses. Neuroradiological findings reveal an ischemic lesion in left PICA region, confirmed by angiography. Clinical and radiological findings suggested complete remission about two months later.