Nineteen patients obstinate with cluster headaches whose pain was not mitigated by standard treatment (Methysergide, caffeine, ergotamine preparation, phenobarbital and analgesics) underwent a double blind control study with single crossover for the evaluation of prednisone therapy. Compared to placebo, a single oral dose of prednisone in 17 cases produced sustained improvement. Maintenance administration of prednisone was also effective in decreasing the frequency of attacks; however a single dose of the steroid when headaches began was effective.