The headache begins immediately or shortly after the aura subsides. For many years migraines and the somewhat similar cluster headaches were thought to be caused by changes in blood flow to the brain. Sophisticated studies of blood flow that are now possible have not supported that theory. Some blood flow changes have been seen during the aura phase, but people who get migraines without an aura apparently don't have any such changes. The newest theory is that some stimulation of the ganglion at the base of the brain, which supplies nerves to the brain's arteries, may be causing the headaches.
Some migraines are mild enough to be treated with simple anti- inflammatories such as ibuprofen.
Most are too severe for this treatment alone and other medications have been developed, some quite recently. The oldest, and still very effective treatment, is to use one of the ergot alkaloids, which may be given orally, as rectal suppositories, or by injection. They are most effective when used as soon as the aura begins. Taking these drugs, at least in pill form, after the headache has begun is less effective. They can also be used prophylactically to prevent headaches from developing.