Corticosteroids appear to be the most rapid-acting of the prophylactic drugs used in the treatment of cluster headache (CH). These agents are frequently empl oyed as a short-term regimen to induce clinical remission. In this study, we as sessed in an open fashion the effect of high dose methylprednisolone (MPD) in a group of 13 patients with episodic CH (3 females and 10 males). On the 8th day o f the active period, MPD was administered intravenously at the dose of 30 mg/kg body weight, as a 3-h infusion in saline. The attack frequency was followed for 7 days. The mean daily attack frequency before MPD administration was statistic ally different from that reported after treatment (respectively: 1.38 ±.0.42 an d 0.83 ±0.78; P=0.05 Student’s t-test). The mean interval between MPD adminis tration and the occurrence of the first subsequent attack was 3.8±2.2 days (ran ge:2-7 days).Only 3 (23%) of 13 patients experienced a complete headache remission. No sig nificant side-effects were noted after MPD administration. These data further d emonstrate that in most patients with episodic CH, high-dose systemic steroid a dministration may invariably interrupt attack recurrence for a few days, but is ineffective in maintaining complete clinical remission. This study also sugests that MPD administered as a solitary dose does not provide any advantage above pr ednisone in CH treatment. Corticosteroids appear to be the most rapid-acting of the prophylactic drugs used in the treatment of cluster headache (CH). These agents are frequently empl oyed as a short-term regimen to induce clinical remission. In this study, we as sessed in an open fashion the effect of high dose methylprednisolone (MPD) in a group of 13 patients with episodic CH (3 females and 10 males). On the 8th day of the active period, MPD was administered intravenously at the dose of 30 mg / kg body The mean daily attack frequency before MPD administration was statistic ally different from that reported after treatment (respectively: 1.38 ± 0. 0.42 an d 0.83 ± 0.78; P = 0.05 Student’s t-test). The mean interval between MPD adminis tration and the occurrence of the first subsequent attack was 3.8 ± 2.2 days (ran ge: 2-7 days). Ofly 3 (23%) of 13 patients experienced a complete headache remission. No sig nificant side-effects were no ted after MPD administration. These data further d emonstrate that in most patients with episodic CH, high-dose systemic steroid a dministration may invariably interrupt attack recurrence for a few days, but is ineffective in maintaining complete clinical remission. This study also sugests that MPD administered as a solitary dose does not provide any advantage above pr ednisone in CH treatment.