PGE2 and TXA2 levels and their modulation by nicardipine, a calcium blocking agent, have been studied in patients suffering from migraine. The levels of both metabolites were determined in saliva obtained during the migraine attacks, during the intervals between attacks, and after 2 months of treatment with nicardipine (20 mg every 8 h.) or placebo. The therapeutic response was evaluated on the basis of the number of migraine attacks. The results show a significant increase in the levels of both eicosanoids during the migraine attacks. In contrast to the placebo group, the number of migraine attacks and the levels of both arachidonic acid metabolites are markedly lower in the nicardipine group. Our results suggest calcium entry into the cytosol as an explanation for the increase in PGE2 and TXA2. Nicardipine interferes with calcium mobilization, thereby inhibiting arachidonic acid metabolite synthesis.