A case of galactorrhea immediately following a reduction mammaplasty is presented. Prolactin levels were elevated postoperatively and could be reduced to normal by a prolactin inhibitor. No other disease or disorder could be found. Based on a review of the literature, it seems that various factors have to contribute to galactorrhea, including stress-related prolactin secretion, rebound phenomenon after discontinuation of birth control pills, and hypersensitivity to prolactin receptors. Their coincidental occurrence, resulting in abundant milk production after surgery, is discussed.