Consumption of caffeine in the diet, both daily and occasional, has a significant biological effect on the nervous system. Caffeine, through various and not yet fully investigated mechanisms, affects headaches. This is especially noticeable in migraine. In other headaches such as hypnic headache, post-dural puncture headache and spontaneous intracranial hypotension, caffeine is an important therapeutic agent. In turn, abrupt discontinuation of chronically used caffeine can cause caffeine-withdrawal headache. Caffeine can both relieve and trigger headaches.