Objectives: Cluster headache (CH) is a rare disease (1 to 3 / 1000), predominant in men (sex ratio: 4 men / 1 woman) and characterized by frequent very painful paroxystic attacks occurring sometimes 8 times by day. CH is a disease without lesion and impairs the quality of life of patients. Attacks occur only on the same hemiface and can last from 15 minutes to 3 hours. The pain is particularly severe and a frequent and extreme psychiatric symptomatology is observed during the attacks. Treatments are rare and not always efficient: sumatriptan, oxygen, LSD, psilocybin. In this paper we try to answer to the question: "What does that make you to have a cluster headache attack ? ", using elicitation interview developed by Vermersch. Patients and methods: Ten patients have been interviewed using elicitation interview (EI) (40-50 mn for one interview). All these patients (7 men and 3 women) T suffer from chronic or episodic CH, with a mean age of 43 years. The patients come from the Lariboisiere hospital (Paris), and more precisely from the center of headache urgency. EI allows describing the pre-reflexive consciousness contents. The method is described in Balzani and coll., and in Petitmengin and coll (see bibliography). Data analysis were performed using Interpretative phenomenological analysis (IPA). Results: From the EI, we have distinguished three phenomenological axes, following Heidegger’s philosophy: 1) An alteration of being-to-the-world with a strong unbearable feeling of imprisonment, and physical restriction. At the same time the patients present a stereotypical and automatic behavior with few motor schemes and escaping strategies. When pain arises, they want to leave and to go very far. Aggressive behavior frequenly occur. Sometimes, the patients are not able to perform the sumatripan injection, due to a motor inhibition. Some patients try to do autohypnosis or other methods to resist to the pain. 2) An alteration of being-to-the self, going from the corporal distortion to the body dissolution. At the onset of symptoms, the patient does the experience of physical deformation, particularly of the face, with strong vegetative symptoms. The patient is not able to control corporeal manifestations: tears, mad thinks, incoherent projects in order to stop the crisis. Some patients want to remove the part of their body where the pain is the most intense (eye, for example). There is a losing of the body limits and a loss of the time orientation. In many cases the pain is unbearable and patients want to commit suicide. At the extreme, the sensation of self seems destroyed, and some patients evoke an experience similar than Near Death Experiences, or describe an experience of swaying in emptiness or imminent death. 3) An alteration of being-to-the-other, going from the imperative solitude to the acceptance for a presence without words. Solitude is the most experience for the patients. They cannot accept anybody. Another person is unbearable, because asking questions about the crisis. In the same time, the patient is scared of this solitude since he is not able to speak about his painful experience. In summary, the structure of the self is altered, and thinking is completely disturbed. The experience of time and space is modified and apragmatism is a consequence of this intense pain. During the crisis, pain is central and the patient lives a kind of dissolution, near death: a self-dismantling. Conclusion: The EI have allowed us to describe precisely the painful experience of subjects with a cluster headache. This experience is very rich and very intense. EI, as a phenomenological method, is a very useful method to describe more precisely the symptomatology of a disease, because it pays attention to the effective experience of the pathological flesh, as compared to the pathological body.