text: why does ice cream cause a headache?   most people have experienced the dreaded ice cream headache at some point. you are minding your own business on a hot summer day, eating something like an ice cream cone, a milk shake, a slurpee, a snow cone... then, suddenly you are hit with the most excruciating headache! fortunately it only lasts about 30 seconds.   so where does this headache come from?   i have not seen a better answer to the question than in this article by joseph hulihan. it's a little technical, but it contains some great information. here's a summary: when something cold touches the roof of your mouth on a hot day, it triggers a cold headache. the cause is a dilation of blood vessels in the head. the dilation may be caused by a nerve center located above the roof of your mouth -- when this nerve center gets cold, it seems to over-react and tries to heat your brain.   therefore, the easy way to avoid "brain freeze" is to keep cold things away from the roof of your mouth!