Migraine is a neurological syndrome characterized by altered bodily perceptions, severe headaches, and nausea. Physiologically, the migraine headacheis a neurological condition more common to women than to men. The word migraine was borrowed from Old French migraigne (originally as "megrim", but respelled in 1777 on a contemporary French model). The French term derived from a vulgar pronunciation of the Late Latin word hemicrania, itself based onGreek hemikrania, from Greek roots for "half" and "skull".

The typical migraine headache is unilateral (affecting one half of the head) and pulsating, lasting from 4 to 72 hours; symptoms include nausea, vomiting,photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound). Approximately one-third of people who suffer migraine headache perceive an aura—unusual visual, olfactory, or other sensory experiences that are a sign that the migraine will soon occur.