Chiropractic manipulation of the neck can occasionally cause severe neurological complications, as demonstrated by this case report. A 59-year-old man who had previously sustained a cardiac infarction and a femoral-popliteal bypass operation, suffered from painful spasms of the cervical muscles for several weeks. After chiropractic manipulation, a left, predominantly brachiofacial, hemiparesis developed during the subsequent 24 hours. Computed tomography demonstrated a recent infarction in the area supplied by the ascending central and parietal branches of the right medial cerebral artery. Doppler sonography revealed occlusion of the right internal carotid artery as the cause. Marked improvement followed hypervolaemic haemodilution daily with 500 ml hydroxyethyl starch and intensive physiotherapy. Blood flow through the internal carotid artery was restored after seven days (demonstrated by Doppler ultrasound). In the presence of arteriosclerotic vessel changes particular care should be exercised in deciding on and execution of chiropractic manipulations.