migraine, Recurrent headache, usually on one side of the head. Severe throbbing pain is sometimes accompanied by nausea and vomiting. Some migraine patients have warning symptoms before the headache, including visual disturbance, weakness, numbness, or dizziness. Migraine attacks can be triggered by a variety of factors, including stress, changes in weather or sleep patterns, and menstruation. Drugs may be taken as an attack begins (to abort it) or daily by patients with very frequent attacks (to prevent them or reduce their severity).