The authors, in order to evaluate the important role of gastrointestinal dysfunction during the migraine attack, have studied 53 patients with migraine without aura during the asymptomatic stage between attacks. Patients were examined functionally with a pH meter test of the gastroesophageal tract over 24 hours and morphologically with esophagogastroduodenoscopy. The results of this study point out that in a high percentage of patients with migraine, both evaluations are normal. The authors suggest the possibility of detecting, even hypothetically, an alteration of the common neurotransmitter substrate in the origin of migraine attacks and accompanying symptoms.