In a double-blind study of 80 migraine patients, headache was precipitated by ingestion of 200 mg tyramine and not by placebo in eight individuals, but retesting of seven of these patients did not produce the same results. Placebo produced as severe headache as tyramine and in an even larger number of patients. It is concluded that dietary tyramine alone is rarely, if ever, the major precipitant of a migraine attack, although the possibility remains that it has such a role in the presence of particular physiologic states.