Recurrent hypersomnia represents a rare pathology, with an etiology difficult to identify. This paper presents a female teenager's case, in the 5th hypersomnia episode, which lasts for one week, being awakened by her parents to eat and go to the toilet. The first episode occurred in December, when she was diagnosed with “Encephalitic reaction with cerebral edema and confusive syndrome. Psychoorganic syndrome. Respiratory virosis” and she was treated with cerebral depletive drugs. The following episodes of hypersomnia occurred at regulate periods of time of 3 weeks, remitted without medication; between the episodes the teenager's condition was without any somatic, cognitive alteration.

All the investigations, including cerebral RMN, were normal, except for EEG, indicating a slow course in all the derivations. The anamnesis information indicating that the hypersomnia episodes were followed by the menstrual cycle, together with the ecography discovery of a right ovarian cyst of 4/4 cm, determined us to introduce oral contraceptives treatment, which lead to the disappearance of the hypersomnia episodes.