Migraine with aura is a common disorder in industrialised countries, affecting up to 5% of the adult population. Although migraine aura is usually a benign disorder, in rare instances it can be the cause of serious neurologic complications. The most common is migrainous stroke, defined as a persistent neurologic deficit following the aura with evidence of brain infarction at neuroimaging and lack of alternative explanations. The most likely pathogenic mechanism is brain ischaemia induced by cortical spreading depression, but other possibilities, such as intracranic arterial dissection or embolism through patent foramen ovale need to be considered. Other complications are migraine-related seizures, which are probably caused by neuronal hyperexcitability in migraineurs, and persistent auras without infarction. These disorders are of both clinical and scientific interest, as they throw light on the complex and not yet fully understood relationship between migraine with aura, stroke and epilepsy.