Galactorrhea can be due to "normal" factors such as an unrecognized pregnancy, trauma, surgery, overexercise or one of a number of drugs (including amphetamine, cimetidine, female hormone replacement therapy, hydroxyzine, methyldopa, nicotine, narcotics, reserpine, antidepressants of the so-called tricyclic type, or verapamil).
Galactorrhea can also be due to "abnormal" factors of a pathologic nature such as cirrhosis of the liver, a false pregnancy (pseudocyesis), renal (kidney) failure, disorders of the spinal cord, or a prolactinoma (a benign pituitary tumor that secretes the hormone prolactin which stimulates milk production).
The word "galactorrhea" comes from the Greek "galaktos" meaning "milk" + "rhein" meaning "to flow" = "to flow milk." (The naturally occurring sugar in breast milk is called galactose.) Galactorrhea is also sometimes called witch's milk.