Mexico's 1920 Cannabis Prohibition

Last verified: April 2026

The Surprising Date Most Americans Don't Know

A piece of history that surprises most U.S. readers: Mexico federally prohibited cannabis in March 1920 — 17 years before the U.S. Marijuana Tax Act of 1937. The 1920 Disposiciones sobre el cultivo y comercio de productos que degeneran la raza (Department of Public Health regulations under President Venustiano Carranza, enacted under the post-Revolution health framework) banned the cultivation, sale, and use of marihuana on public-health and racial-degeneracy grounds.

The Carranza Framework

The 1920 prohibition emerged from the public-health authority of the Departamento de Salubridad Pública under the Constitution of 1917. President Venustiano Carranza — the post-Revolution constitutional president — signed regulations that grouped cannabis with opium, coca derivatives, and other substances under a "race-degenerative" framework that combined:

• Public-health rationale — the early-20th-century medical belief that cannabis caused madness and physical decline.
• Racial-degeneracy ideology — eugenic-era thinking that linked drug use to "racial decline."
• State-building authoritarianism — the post-Revolution Carranza government used regulatory authority to project a modernizing image.
• Practical class concerns — cannabis use was associated with rural campesinos and the urban poor; prohibition aligned with elite "civilizing" projects.

The Prohibitionist Literature

Mexican prohibitionist publications between 1900 and 1920 — particularly the writings of physicians and public-health officials — established a vocabulary about cannabis ("la mariguana") that would prove enormously consequential. The historian Isaac Campos, in Home Grown: Marijuana and the Origins of Mexico's War on Drugs (2012), documents how Mexican medical-and-popular discourse described cannabis as inducing:

• Madness (locura)
• Violence and homicide
• Racial regression
• "Marijuana psychosis"

This framing was substantially generated in Mexico during the prohibition decades.

The Export to U.S. Discourse

Between 1910 (the start of the Mexican Revolution) and the late 1930s, large-scale Mexican migration to the U.S. Southwest carried cannabis use — and the Mexican prohibitionist framing — north. U.S. anti-cannabis discourse in the 1920s and 1930s drew explicitly on Mexican prohibitionist literature, with Harry J. Anslinger, the first commissioner of the Federal Bureau of Narcotics (1930–1962), citing Mexican-origin claims about cannabis-induced violence and madness in his congressional testimony for the Marijuana Tax Act of 1937.

The Racialized U.S. Frame — Imported from Mexico

The U.S. Marijuana Tax Act of 1937, championed by Anslinger, was built atop a racialized narrative that combined the Mexican prohibitionist framing with U.S. racial anxieties of the era:

• Anslinger's congressional testimony emphasized "Mexican" and "Negro" users.
• Reefer Madness (1936) and the broader cinema-and-press hysteria of the late 1930s racialized cannabis as a Mexican-import problem in U.S. public opinion.
• The very word "marijuana" — vs. the older U.S. medical name "cannabis" — was popularized in U.S. discourse to emphasize the substance's foreign-Mexican character.

The legacy of that framing is still present in U.S. cannabis politics; reckoning with it is part of why social equity is a core legal-cannabis principle today.

Pancho Villa, Zapata, and the "La Cucaracha" Question

The Mexican Revolution (1910–1920) generated rich folklore about cannabis use in Pancho Villa's División del Norte and Emiliano Zapata's Liberation Army of the South. The most famous artifact is the corrido "La Cucaracha", with its verse:

La cucaracha, la cucaracha, ya no puede caminar
porque no tiene, porque le falta, marihuana que fumar.

Whether actual revolutionary soldaderas and soldiers smoked cannabis in significant numbers is historically contested. Most serious historians (Isaac Campos and others) treat the folklore as cultural symbol more than ethnographic record. The Pancho Villa cannabis legend — Villa as personal user — is largely a 20th-century myth that was retroactively grafted onto the Revolution narrative.

The 1925 League of Nations Convention

The 1925 International Opium Convention (Geneva), signed by Mexico, brought cannabis under international drug-control auspices for the first time. Mexico was an early adopter rather than a reluctant signer. The 1925 convention paved the way for the 1961 Single Convention on Narcotic Drugs, which Mexico also signed and which still binds Mexico\'s formal international obligations on cannabis.

From 1920 to the SCJN

Mexican cannabis prohibition continued throughout the 20th century with periodic intensification:

• 1925 — League of Nations convention; cannabis listed.
• 1947 — Strengthened Ley General de Sanidad (predecessor of LGS) controls.
• 1961 — Single Convention on Narcotic Drugs ratification.
• 1973 — Updated Código Penal Federal narcotics provisions.
• 1984 — Codified federal narcotics regime largely as it stands.
• 2009 — Ley de Narcomenudeo establishes 5-gram personal-use threshold.
• 2015–2021 — SCJN constitutional reform line.

Reading the 1920 Date Today

The 1920 prohibition matters in 2026 for three reasons:

• It corrects the U.S.-centric narrative that places cannabis prohibition origins in the 1937 Marijuana Tax Act.
• It contextualizes Mexico's century-long prohibitionist legal tradition that the SCJN is now dismantling.
• It reframes the Mexico-U.S. cannabis-policy relationship: Mexico was not the recipient of U.S. drug-war policy — Mexico, in part, generated it.

Further Reading

• Isaac Campos, Home Grown: Marijuana and the Origins of Mexico\'s War on Drugs (UNC Press, 2012).
• Carlos A. Pérez Ricart, scholarly work on Mexican drug-policy history.
• SCJN historical archives — for the constitutional reform line.

Related on this site: Mexican Cannabis Activism, Cartels & Cannabis Reframed, Cannabis & Indigenous Mexico.