Indomethacin, a new nonsteroid anti‐inflammatory agent causes headache, a marked decrease in cerebrospinal fluid pressure, and an increase in retinal arterial pressure, while it produces little and inconstant change in the pressure of the carotid and brachial arteries. Despite the headache, indomethacin was investigated in sub;ects with vascular headache because of its vasoconstrictor action. Clinical improvement similar or slightly inferior to that with ergotamine was observed.