A method of preventing the headache phase of migraine in a human comprises administration of a 5HT.sub.1 receptor agonist or administration of an over-the-counter or nonprescription drug to said human exhibiting prodrome symptoms of migraine. Suitably, the method comprises administration of a migraine headache phase-preventing effective amount of the 5HT.sub.1 agonist or over-the-counter or nonprescription drug. There is disclosed a preemptive prophylaxis migraine method using the following cognitive tests: Simple Reaction Time; Running Memory Continuous Performance Task; Matching to Sample; Mathematical Processing Task; and interpreting the results as a percent of baseline indicator of need for prophylaxis.