The aim was to evaluate if foods, against which patient has IgG antibodies, trigger tension type headache (TTH). 22 patients (8 male, 14 female; 8 chronic TTH, 14 frequent episodic TTH) were recruited. The study had four periods: cooperation, provocation, free diet month and elimination were determined. At the cooperation perido patients’ cooperation abilities were checked. All patients were screened for 271 different antibodies against foods using Imupro300. Thus a list of food sensitivity was described for each patient. In provocation period,those detected foods were added to diet. In elimination period, those foods were eliminated from the diet with false foods added. In free diet month, there were no restrictions. Patients recorded the number of the days with headache as well as headache frequency, severity and duration and analgesic intake. These headache features in cooperation, provocation and elimination periods were compared. In the elimination period there was a significant decrease in the number of days with headache, headache frequency and duration in all patients. A significant increase in these three features were observed in the provocation period. In chronic TTH patients, only the number of the days with headache significantly increased in provocation period. IgG antibodies against foods may have a role in TTH. Number of days with headache, headache frequency and duration can be decreased by eliminating related foods from the diet, and this can be a part of the treatment. IgG antibodies against foods may be one of the pathophysiological mechanisms triggering TTH.