A solution containing an attenuated, live culture preparation of theBacillus Calmette Guerin (BCG) strain of Mycobacterium bovis with potential immunostimulating activity. Although the precise mechanism of action is unknown, upon intravesical administration, attenuated, live BCG bacteria in the solution come into direct contact with the bladder wall, inciting an antitumor granulomatous inflammatory reaction. Check for active clinical trials using this agent. (NCI Thesaurus)