Many factors should be considered when an episodic migraine worsens and becomes chronic. Prolactin (PRL) was linked to the origin of pain in patients with microprolactinomas who developed different types of headaches. Our team carried out studies on 27 patients with a background of episodic headaches that became chronic. The patients were evaluated by means of a general examination, a neurological examination and a hormonal profile. Of the 27 patients, 7 of them had an increased level of prolactinaemia. All the patients were women, ranging from 17 to 57 years of age. Four of them had a pure form of migraine without aura, whereas 3 patients had both migraines without aura and tension–type headaches. They suffered from headache for a period ranging from 3 to 32 years and their headache became chronic 4–12 months prior to the visit. Their headache did not change in type, but only in severity and frequency. Two patients had no symptoms referable to high PRL levels; 4 patients had irregular menses or amenorrhoea. One of these patients also suffered galactorrhoea and two of these patients had a microprolactinoma at MRI; one patient was using estroprogestinic drugs, so her menstrual alteration could not be considered. The patients were followed–up for a period of 6–16 months. Six patients responded favourably after being treated with cabergoline, although some had already tried other drugs, which, however, had no effect on their headache. One patient improved after ceasing to take estroprogestinic, in spite of increased levels of PRL. Therefore, on this basis, PRL levels should always be considered when headache worsens. It is an adjunctive worsening factor, which can be easily eliminated.