In premenopausal women without amenorrhoea and with normal prolactin, approximately 30% of cases of galactorrhea are idiopathic; in postmenopausal men and women, galactorrhea usually indicates an underlying pathology. Measure serum prolactin in all premenopausal women with a negative pregnancy test and in all postmenopausal men and women. Consider referral to an endocrinologist for galactorrhea associated with unexplained hyperprolactinemia, hypogonadism, postmenstrual disorders, frequent menstrual disorders, galactorrhea with normal prolactin levels, or diagnostic uncertainty. A unilateral, blood-stained or serous discharge may indicate malignancy; consider suspected breast cancer. An example is a 30-year-old woman with a three-month spontaneous bilateral milk discharge from the nipples 14 months after the end of breastfeeding, without pain, sensitivity or lumps, requiring frequent replacement of breast pads due to the volume of the discharge. [1 of the contents]