The Marihuana Tax Act of 1937 was a significant piece of legislation that resulted in the effective prohibition of marijuana in the United States. Originating in a period characterized by heightened fears about drugs and their influence on society, the Act was championed by Harry Anslinger, the head of the Federal Bureau of Narcotics. Anslinger and his allies argued that marijuana was a dangerous substance that led to violent behavior, addiction, and other social issues. The narrative constructed around marijuana included exaggerated claims about its effects, furthering public and political support for the legislation.

The Act required anyone dealing in marijuana to register and pay an excise tax that was exorbitantly high, making legal trade extremely difficult. By enforcing strict record-keeping and taxation, it eliminated the commercial market for marijuana and severely restricted personal use. The potential for heavy penalties for non-compliance further discouraged legal possession. This Act also reflected broader societal shifts in the United States during the 1930s, as the country grappled with the economic challenges of the Great Depression and sought to impose a sense of moral order.

As a result of the Marihuana Tax Act, marijuana underwent a transformation in public perception from a commonly used substance to one shunned and demonized. The law set a precedent for subsequent drug laws and policies in the U.S. and contributed to the rise of the War on Drugs in later decades. The stigmatization of marijuana also influenced social attitudes, leading to decades of criminalization and enforcement against cannabis users, growers, and distributors.