Migraine is a very common type of primary headache that tends to have vasodilation during the attack period, resulting in increased blood flow in the brain, which increases intracranial pressure relative to normal. When the intracranial pressure is increased, it often causes eye swelling and pain. The first one is related to the reflex nausea caused by the increased intracranial pressure, and the second one is related to autonomic dysfunction. Migraine induces autonomic dysfunction, the latter including sympathetic and parasympathetic nerves. The smooth muscle movements of the internal organs are mainly innervated by these two nerves, and when they are disturbed, the contractions of the internal organs become functionally abnormal and spasms tend to occur in the stomach and intestines. Stomach spasms can lead to nausea and, in severe cases, vomiting, and intestinal spasms often lead to diarrhea. Therefore, many patients will have nausea and vomiting with the feeling of wanting to relieve the bowels during a headache attack.