Reference to people suffering bouts of severe headache with associated vomiting and visual aura may be found in texts that date back 5000 years but the first clear description of migraine as a distinct clinical entity was provided by Aretaeus of Cappadocia in the second century AD. Today, at least 80% of women experience headaches in adult life and in approximately a quarter of these cases the pain is recurrent and incapacitating. When each episode of headache lasts between 4 and 72 hours and is accompanied by nausea, vomiting, photophobia or phonophobia, the symptoms fulfil the International Headache Society's current definition of the syndrome called migraine, detailed in Table 1.