1940: The Year Mexico Legalized Drugs


This is a guest blog by Dr. Benjamin T. Smith from the University of Warwick. This piece was originally published by the BBC.


On 5 January 1940, Mexico’s left wing president, Lázaro Cárdenas, signed the new Federal Regulation of Drug Addiction into law. The new legislation was truly revolutionary. It swept away the old punitive edicts on drugs offences, authorised doctors to prescribe narcotics to addicts, established out patient clinics to attend to these addicts, and made broader pleas to treat addicts as ill rather than as criminals or pariahs.


Within a month, the law had taken effect. The selling and purchasing of small amounts of drugs, including marijuana, cocaine, and heroin were effectively decriminalized. Small-scale drugs offenders were released from prison and the city’s drug addiction clinics. Police officers dramatically reduced arrests for drug crimes. And half a dozen drug dispensaries were established throughout Mexico City.


The law was deemed a major success. By mid March, at least a thousand addicts attended these dispensaries each day, buying small, controlled doses of cocaine and morphine under medical supervision and at market value. Doctors and journalists spoke out in favour of the change. “To attract [the drug addict] rather than persecute him, to register him and make him submit to medical and psychological treatment…will constitute a fundamental means of combatting addiction”. So did drug addicts. Homeless heroin addict, Rompepechos, testified, “We only want that they say the truth…that they dose us according to our physical state so we can reintegrate into society and return to our jobs. Now they are doing this. Tell your readers that we are thankful to the Health Department, very thankful.”


The cheap prices that these clinics offered also crippled the illegal trade. The government morphine cost 3.20 pesos a gram. On the street, the same amount of heroin cost between 45 and 50 pesos.  Furthermore it was heavily diluted with lactose, carbonate of soda and quinine. A pure gram probably cost nearer 500 pesos. Such low prices undercut the dealers. Mexico City’s pushers were losing 8000 pesos a day.


Yet, within six months, the legislation was overturned. On 7 June 1940 the government declared that wartime shortages of both cocaine and morphine made the scheme unworkable. The following month the old punitive legislation of 1931 was reintroduced.



The story of Mexico’s brief flirtation with legalization has a profound contemporary resonance. Over the past decade, the country’s war on drugs has cost the lives of an estimated 160,000 citizens. Yet around the world, calls for legalization are gathering pace. Experts point to the success of Portugal’s experiment with decriminalization. US states vie to collect the tax revenue from legalized marijuana. And in June this year even the UK Times called for treating addiction as a health problem rather than a crime.


In the current international atmosphere, Mexico’s 1940 policy looks curiously prescient.

Yet, questions remain. Why did they legalize drugs? And if it was so successful, why did they suddenly stop?




In many ways, Mexican legalization was also the brainchild of one man. His name was Leopoldo Salazar Viniegra. He was doctor by training. He studied psychiatry and neurology in France before eventually returning to Mexico. Here, in 1938 he was put in charge of Mexico City’s Drug Addiction Hospital. The place was full to capacity. Like the US, Mexico imprisoned or locked up thousands of addicts a year.



Over the next two years, Salazar would produce a series of academic articles, journalistic interventions, and press interviews, which not only criticised the prohibitionist status quo but also laid out the framework for a better system.


In essence his arguments were three fold. First, in his breakout work “El Mito de Marijuana”, he argued that the dangers of marijuana were greatly overstated. Systematically reviewing medical studies of the drug, he pointed out inaccuracies, pieces of hearsay, and misapplications of the data. In one particularly powerful piece, he mocked American doctors’ appreciations of the drug, which he argued were based on misquotations of Charles Baudelaire’s hash-inspired poetry. He also presented his own research on the subject conducted over seven years among a wide range of patients, including drug addicts, the insane, a handful of unsuspecting medical colleagues and politicians and his nine-year-old nephew, who had mistakenly smoked one of his marijuana-laced cigarettes. He concluded that, irrespective of class, education or age, marijuana did little except dry the lips, redden the eyes, and produce a feeling of hunger.


Second, in a series of articles and interviews with the press he argued that drug addiction should be treated as a public health problem and not as a crime. Building on his work on marijuana, he claimed that there was no intrinsic link between drug addiction and criminality. In fact, it was only the high price of drugs, generated by prohibition, that led users to commit crimes. Rather than stocking the prisons with users, he suggested a combination of education, drug treatment hospitals, and psychiatric help.


Third, he suggested ending prohibition and establishing a new state-run drug monopoly. Prohibition, he argued, had generated the market for illegal drugs, and stopping drug traffickers was almost impossible. Furthermore, the illegal trade had two important supplementary consequences: it corrupted the Mexican police force, which was paid to protect the big dealers, and it pushed up prices, forcing users into crime. As a result, he reasoned, the best way to deal with drug addiction was not through prohibition but state control. A state drug monopoly that sold drugs at wholesale prices would put the dealers out of business, reduce police corruption, and allow users to feed their habits without recourse to crime.


Salazar’s conclusions are both attractive and modern. They were based on extensive medical research, presented in an intelligent, rational and somewhat ironic manner, and in many ways, echo contemporary critiques of drug policy.


Why stop?


So, if the legalization experiment was a success, why did it end so quickly? According the official government statement, the constraints on morphine and cocaine imports caused by the war in Europe made the system unworkable. But, as you can imagine, there was more to the end of the experiment than this. Somewhat inevitably, it involved the United States.



Since Salazar started voicing his support for legalization, US anti-drugs crusaders had sought to pressure the Mexican government to shut him up. John Buckley, a Texas customs man called Salazar’s plans “the outpourings of an educated nigger”.


But, it was puritanical head of the Federal Bureau of Narcotics, Harry Anslinger, who eventually put an end to the experiment. Just five days after the introduction of the law, the US state Department invoked the 1935 amendments to the Law of Importation and Exportation of Narcotic Drugs. The amendments allowed the US to establish an export embargo on narcotics like morphine and cocaine when it deemed the objectives of a country to be neither medical nor scientific.


Although Mexico’s foreign ministry tried to argue the case, claiming that the experiment was working and certainly more efficient that the previous punitive system; Anslinger and the US state department remained defiant. In May, all exports of morphine and cocaine were stopped. Without the cooperation of war-locked German drug companies the Mexican authorities were forced to give up.


Author: Dr. Benjamin T. Smith. Twitter: @benjamintsmith7