1. Cluster headache is a severe unilateral head or facial pain, which lasts for minutes or hours, commonly associated with ipsilateral lacrimation and blockade of the nostril. It usually recurres once or more daily for a period of weeks or months, separated by intervals of freedom. The sphenopalatine ganglion seems to play a very important role in its pathology, 2. We created a technic of alcohol infiltration of this ganglion through a supra-zygomatic way, based on the research of the maxillary nerve by neurostimulation and the bone contact with the pterygoid process. 3. We observed a relief of pain and parsympathetic disturbances in more than 85% of our 120 cases, with a follow up between 6 months and 4 years. 4. Results obtained are discussed and analysed in connection with the definition of cluster headache. (Acta anaesth. belg., 1981, 32, 101-107).