Beginning in the 1910s, states began to ban the sale of marijuana, eventually leading to a bill called the Marijuana Tax Act in 1937, which decreased the amount of hemp (a version of a cannabis plant) allowed to be produced in the U.S. Later on in the century, the stigma around marijuana grew and Richard Nixon signed into law the Controlled Substances Act, which included marijuana on a list of federally banned drugs alongside heroin, cocaine, and other narcotics.