Cyclic mastalgia of varying intensity occurs every month in at least 70% of women, persistent pain in the mammary glands of moderate and severe degree is occur in about 50% of patients with benign mastopathy. The cause of mastodynia is the morphofunctional rearrangement of the glandular and stromal components of tissues with the expansion of ducts and proliferation of epithelial structures due to a lack of progesterone and an increase in prolactin levels. Therapy for cyclical and chronic mastalgia is empirical and not always effective. Herbal medicine with Vitex agnus-castus is a reasonable alternative to hormonal treatment for women suffering from cyclic mastalgia in combination with other manifestations of premenstrual syndrome. The main effect of such drugs is an increase of luteinizing hormone and progesterone synthesis, effect on the hypothalamic-pituitary system, prolactin and endorphins release, which can increase the level of endogenous opioids.Purpose of the study: to study the effect of the phytopreparation Prefemin (Vitex agnus-castus extract Ze 440) on the intensity of chronic pain syndrome in women with diffuse non-tumor breast lesion. Materials and methods. The study involved 30 women aged 22 to 43 years with various types of benign breast diseases and chest pain lasting at least 3 months. In 12 patients there was diffuse fibroadenoma, in 18 – diffuse cystofibroadenoma (small cystic variant) and duct ectasia.Results. Therapy with Prefemin (Ze 440) allowed to completely eliminate pain syndrome in 93.3% of women and to reduce the frequency of mastodynia in the group with moderate severity in 90.0% of patients with diffuse fibroadenoma and cystofibroadenoma.Conclusions. Phytopreparation Prefemin, which is obtained from the medicinal plant Vitex agnus-castus, has demonstrated high efficacy in the mastalgia treatment in women with diffuse fibrocystic breast disease. This drug was well tolerated and there were no side effects.