Significantly lower met-enkephalin levels were found in CSF from cluster headache sufferers as compared to age-matched healthy volunteers, whereas it was not possible to demonstrate any clear-cut difference for ß-endorphin. CSF opioid levels may rise following manual or electroacupuncture. It was studied whether traditional Chinese (manual) acupuncture affected CSF levels of met-enkephalin or (ß-endorphin in these patients, and to what extent this treatment would be beneficial for the headache. A significant rise in lumbar CSF met-enkephalin levels was found, whereas no clear change in ß-endorphin levels was obtained. The treatment was, however, of little value in preventing the headache.