5-(Piperidin-4-yl)imidazolidine-2,4-dione can be used as CGRP-receptor antagonists to treat migraine and other headaches, neurogenic vasodilation, neurogenic inflammation, thermal injury, circulatory shock, flushing associated with menopause, airway inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD)?, and other conditions the treatment of which can be effected by the antagonism of CGRP-?receptors.