The use of recombinant bovine somatotropin In the United States has been a hot button topic since its market debut as Posilac by the Monsanto Company in 1994. More research than any other veterinary related drug surrounds the Posilac? product assuring its safety and efficacy as a lactational enhancement tool. This paper will attempt to clearly demonstrate the role rBST plays on commercial dairies, and the considerations for incorporating this tool into a herd's management scheme. It is of monumental importance that all veterinarians understand the technology and its use in animal agriculture in order to act as an accurate source of information for the consumer and dairyman alike.