Many dietary factors have been implicated as possible precipitants of headache. There have been recent differences of opinion with regard to the effect of the artificial sweetener aspartame as a precipitant of headache. To assess the importance of aspartame as a dietary factor in headache, 190 consecutive patients of the Montefiore Medical Center Headache Unit were questioned about the effect of alcohol, carbohydrates and aspartame in triggering their headaches. Of the 171 patients who fully completed the survey, 49.7 percent reported alcohol as a precipitating factor, compared to 8.2 percent reporting aspartame and 2.3 percent reporting carbohydrates. Patients with migraine were significantly more likely to report alcohol as a triggering factor and also reported aspartame as a precipitant three times more often than those having other types of headache. The conflicting results of two recent placebo-control studies of aspartame and headache are discussed. We conclude that aspartame may be an important dietary trigger of headache in some people.