Fifty-two randomly selected patients diagnosed as having either active episodic or chronic cluster headaches were evaluated for symptomatic response to oxygen inhalation. At the onset of attacks, 100% oxygen was administered through a facial mask at a rate of 7 liters per minute, for 15 minutes. Each patient self-treated ten attacks, and timed the rated reduction of pain. A successful treatment result required complete or almost complete reduction of pain in seven of ten attacks, within 15 minutes.In a second (crossover) trial involving an additional 50 patients, sublingual ergotamine tartrate (ErgomarÒ) was compared to oxygen inhalation for symptomatic relief of cluster attacks. Each patient treated ten attacks with either preparation in accordance with the crossover design. Oxygen was administered as described above. Sublingual ergotamine was used every five minutes, to a maximum of three tablets, if necessary.In the first trial 3952 (75%) of patients obtained significant relief from cluster pain. The greatest benefit (92.9%) was found among episodic patients under 50 years of age. The least benefit (57%), was found among chronic patients over 49 years of age. In the second trial, results among oxygen users were better (82%) than those of ergotamine users (70%), but not significantly. Rapidity of relief was similar in both groups.The results of both series indicate that oxygen inhalation is an efficacious symptomatic treatment for cluster attacks. It is superior to ergotamine since there are neither complications nor contraindications to its use. Ergotamine, however, has the advantage of convenience.