The study was divided into 2 different parts. In the first, the clinical charts of NCWS patients were retrospectively reviewed, comparing the characteristics of the ones suffering from nickel allergy with those who did not suffer from nickel allergy, using, as control group, 70 IBS patients. In the second, the investigators prospectively surveyed adult patients with functional gastroenterological symptoms (Rome III criteria) and a definitive diagnosis of NCWS, comparing the characteristics of the ones suffering from nickel allergy were compared with those who did not suffer from nickel allergy, using, as control group, 70 patients with functional gastroenterological symptoms.