Objective: To investigate the central trigeminal circuits in migraine patients. Materials and methods: Short latency responses can be recorded in sternocleidomastoid (SCM) muscles after stimulation of the trigeminal nerve (trigemino-cervical reflex). This brainstem reflex was investigated in 20 healthy subjects, in 20 patients suffering from migraine with aura (MWA) and in 20 patients suffering from migraine without aura (MWOA) during and between the attacks. Results: The trigemino-cervical responses were bilaterally abnormal in 17 patients with MWA and 15 patients with MWOA during the headache attacks, in 11 patients with MWA and in 10 patients with MWOA during the interictal period. In the patients with normal trigemino-cervical responses during the pain-free phase the triptan was significantly more effective at relieving headache. Conclusions: Our findings further support and emphasise the role of the trigeminal system in the pathogenesis of migraine. The bilateral location of the abnormalities suggests a centrally located dysfunction. Therefore, the trigemino-cervical reflex is sensitive in disclosing a disturbed brainstem activity and may be an index of neuronal activity in the human brainstem; moreover their assessment may help as valuable prognostic tool for predicting the efficacy of triptans therapy.