Recombinant Bovine Somatotropin (rBST) is a milk production enhancer, a product of industrial microbiology. First approved for commercial sale in the United States (U.S.) by the Food and Drug Administration (FDA) in 1994, rBST has been immersed in controversy since the early 1980s. Conflicts among major players with interests in rBST have shaped the product's image and influenced its use. Players with interests in the product include government agencies, Monsanto Corporation (the first firm approved to sell rBST), other firms seeking commercial approval to sell rBST, dairy farmers, and consumers.