Well, that would depend if we are talking migraine or a headache.
There is a world of difference.
As an occasional migraine sufferer, there can only be one medication that can control the pain and other symptoms caused by an attack.
Sumatriptan, which belongs to a group of medicines called 5-HT receptor agonists. They work because migraine may be due to temporary swelling of blood vessels in the head, this group of medicines work by reducing the size of the blood vessels, thereby giving relief from this sometimes, potentially debilitating condition.
For a 'normal' headache I would use Excedrin, which is unavailable and unlicensed for use in the UK.
I load my case with them whenever I visit the USA.