Today among all endocrinological disease in women thyroid pathology is the second only to diabetes. Premenstrual syndrome (PMS) plays a leading role in reducing the quality of life for women of the reproductive age. The manifestations of PMS are particularly worse in women with hyperthyroidism. We examined 35 patients with premenstrual syndrome and / or irregular menstruation with concomitant hyperthyroidism. In the examined patients the nature of the menstrual cycle, the degree of manifestation of premenstrual syndrome, the level of PRL and its biologically active fraction (BFA), LH, FSH, estradiol (E2), progesterone (Pg) were analyzed. In order to correct the detected impairments a dose of up to 30 drops of Mastodinon twice a day for three menstrual cycles was used.Mastodinon caused a significant decrease in the levels of total prolactin (15,5 ± 1,0) IU / l, BFA to (8,5 ± 0,7) IU / l and its contents - to the (54,7 ± 4, 5)%, significant increase in LH concentration to (9,3 ± 0,6) IU / l, FSH - to (7,7 ± 0,7) IU / l, E2 - up (179,2 ± 9,9) ng / L and Pg - to (20,5 ± 1,8) mg / l. Restoration of ovulatory cycles occurred in 86.0% of patients, regular menstrual cycles were established in 94.3% of patients, all patients had normal length of the menstrual cycle, duration and volume of menstrual bleeding. Use of Mastodinon led to the elimination of Algodysmenorrhea, emotional and psychological, neurovegetative, vegetative vascular and endocrine-metabolic manifestations of PMS in 94.3% of patients. After using Mastodinon for 3 menstrual cycles breast secretions continued only in 4 (11.4%) patients. Thus the use of Mastodinon had positive effects on the menstrual function and PMS by eliminating hyperprolactinemia and restoring the pituitary regulation of reproductive function.