Opinions are mixed as to the role caffeine plays for headache sufferers.
There's a small number of patients who have true vascular headaches who benefit from caffeine in their regimen, but that's greatly exceeded by the number of folks who get a headache when they miss their scheduled cup of coffee or scheduled soft drink. She says caffeine constricts the flow of blood to vessels in the head that have become dialated and this helps reduce the pain. This has been Ask a Doctor presented by Texas Medical Association.