Cluster headache (CH) is one of the most painful primitive headaches that exists. Since 1991, the subcutaneous administration of sumatriptan (SCS) in the treatment of acute attacks has proved to be rapid and effective. Moreover, SCS has an excellent safety-efficacy ratio. To date, there is no information on the modalities of SCS use by CH patients, and on its possible overuse. In fact, some patients have noticed that the use of this drug on a regular basis modifies the evolution of attacks. We retrospectively studied, in 67 patients admitted for CH, the modalities of self-administering SCS the subjective feeling of medication overuse and its repercussions on attacks. A total of 47 patients used exclusively SCS as an acute treatment, 30 of whom had used more than two injections daily. Four patients whose use of SCS was the highest had also been drug addicts. Twenty-two patients using exclusively SCS thought that sumatriptan could have modified the evolution of attacks: 20 patients thought that the attacks occurred more frequently; 11 commented that the attacks became more intense, and the remaining 11 patients stated that sumatriptan had become less efficient. In CH, overuse of sumatriptan could aggravate the evolution of attacks. Further research is needed to corroborate this argument.