The Federal Bureau of Narcotics (FBN) was an agency of the United States Department of the Treasury. Established in the Department of the Treasury by an act of June 14, 1930 consolidating the functions of the Federal Narcotics Control Board and the Narcotic Division. These older bureaus were established to assume enforcement responsibilities assigned to the Harrison Narcotics Tax Act, 1914 and the Narcotic Drugs Import and Export Act, 1922. (aka Jones-Miller Act)
Harry J. Anslinger was appointed its first commissioner by Secretary of the Treasury Andrew Mellon under President Herbert Hoover. Under Anslinger, the bureau lobbied for harsh penalties for drug usage. The FBN is credited for criminalizing drugs such as cannabis with the Marijuana Tax Act of 1937, as well as strengthening the Harrison Narcotics Tax Act of 1914. Even so, the main focus of the FBN was fighting opium and heroin smuggling. One instance against opium was The Opium Poppy Control Act of 1942. To that end the FBN over time established several offices overseas in France, Italy, Turkey, Beirut, Thailand and other hotspots of international narcotics smuggling. These agents (never totaling more than 17) cooperated with local drug enforcement agencies in gathering intelligence on smugglers and also made undercover busts locally. The work against heroin and opium was however hamstrung by US foreign policy considerations: during the Vietnam War for instance great importance was placed on investigating minor Vietnamese smugglers that could be connected to the resistance while investigations of large scale smugglers from the US ally Thailand were left unfinished.