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When and Why Did Cannabis Become Illegal?

Updated August 8, 2022

With the fight to legalize cannabis well underway, many people wonder how cannabis ever became illegal in the first place. A combination of factors paved the way for making this natural substance illegal, despite a long history of its use.

To understand when and why cannabis became illegal, you also need to understand a little bit about its history of use over the years and the public’s opinion.

Cannabis Use Before the 20th Century

Before the 20th century, hemp was a very popular crop, widely cultivated throughout the 1600s to the 1890s. Hemp production even had governmental support, with the American government supporting its production for use in rope, clothing, and sails on ships during the 17th century. During this time, it was also common to see cannabis included in medicinal tinctures.

It was also very common, starting around the 1850s for people to visit oriental-style hashish bars to enjoy recreational cannabis use. Bars in this style were commonly found throughout most of the major cities in the United States, showing the common acceptance of marijuana at the time.

It Was Required to Be Listed in 1906

In 1906, the Pure Food and Drug Act made the requirement that any over-the-counter medication that included cannabis would include it in the list of ingredients. At the time, there was still no inkling of the future illegality of this particular ingredient. The Pure Food and Drug Act also had similar requirements for certain other drugs.

Early Cannabis Bans


California was the very first state within the United States to ban cannabis, doing so in 1913.

This came from the fact that at the time, the California State Board of Pharmacy was running one of the most aggressive campaigns against narcotics. Not only was it among the most aggressive, but it was also among the first anti-narcotic campaigns.

Interestingly enough, there was minimal press coverage of the cannabis ban in California, so it did not initially affect the country as a whole.


The following year, Utah joined California in its ban of cannabis. Historians actually directly link this to the banning of polygamy in 1910. When that ban took place, people who practiced polygamy moved to Mexico. They began returning around four years later, bringing cannabis with them.

In 1914, Utah finalized the Mormon Religious Prohibitions law, resulting in cannabis becoming illegal.

Other States

Massachusetts introduced regulations to limit the sale of cannabis as well as cannabis-derived products starting in 1911. Maine and New York did the same in 1914. In these cases, there were just restrictions put into place, not a complete ban on cannabis.

Other States Followed

Over the course of the following two decades, more states joined California and Utah in banning cannabis until 29 states had banned it. The reasons for the bans varied slightly, with racism being a common reason. Some states also banned it due to fears that heroin addicts would begin using marijuana.

The International Opium Convention

As of the International Opium Convention in 1925, the official stance of the United States was to support the regulation of what is referred to as Indian hemp. This term was used to describe cannabis rich in THC. At this convention, exporting Indian hemp and derivative products, including hashish, was restricted in the case of exports to countries that banned it already.

The FBN and Uniform State Narcotic Act

In 1930, the government created the Federal Bureau of Narcotics. The commission of the organization was Henry J. Anslinger from the start and until 1962.

The FBN strongly urged states to ban cannabis as a way to control the “problem” associated with marijuana themselves. In 1932, the organization pushed for the adoption of the Uniform State Narcotic Act. This act urged the states to form a united front with uniform laws to help fight against trafficking of narcotics and to help manage that trafficking. By the time the mid-1930s were underway, every single state in the United States had at least some regulations related to cannabis.

At the time, experts who conducted research into cannabis concluded that it was linked to crimes. The research also indicated that cannabis use was connected with a rise in social problems. When viewed with a modern lens, it becomes clear that this research likely had some strong inherent bias.

Cannabis in Media in the 1930s

Cannabis also experienced a few key moments in terms of media and movies during the 1930s. 1936 saw the release of “Reefer Madness.” That year was also when the Motion Pictures Association of America chose to ban movies from including any drug use within films.

The Marijuana Tax Act

1937 marked the true beginning of the criminalization of cannabis with the Marijuana Tax Act. This act made it legal to possess marijuana if it was for industrial or medicinal purposes, and the person in question paid the excise tax. Anyone possessing marijuana without meeting these requirements would face charges.

Pharmaceutical Companies Were Against Cannabis

The pharmaceutical companies chose to join those in favor of banning cannabis for a relatively simple reason – they could not determine the proper dosing. Without proper dosing, it was impossible to incorporate cannabis into pharmaceutical products, so the companies could not make a profit off of it.

When the American Medical Association supported the Marijuana Tax Act, it became almost guaranteed to pass.

Racism Towards Mexicans Played a Key Role

Although you are unlikely to realize it at first, one of the biggest factors that led to the criminalization of cannabis was racism against Mexicans. The early 1910s saw the end of the Mexican Revolution, which resulted in many Mexicans immigrating to the United States, especially the southern areas.

These new immigrants brought customs, culture, and language with them, including using cannabis as a relaxant and medicine. It did not help matters that the Mexican immigrants referred to the plant as “marihuana” while it had previously only been called “cannabis” in the United States. This gave the media another tool to help play on fears associated with racism.

Essentially, the media was able to label the Mexican immigrants as disruptive and dangerous, pointing to factors like their use of marihuana, which most Americans were unfamiliar with. As Americans did not realize this was the same cannabis they already used, they accepted the lies very easily.

It Became an Excuse to Get Rid of Mexican Immigrants

A few decades before, San Francisco had dealt with Chinese immigrants by outlawing opium. It then used the illegality of opium as an excuse to search Chinese immigrants, as well as detain and deport them. The country as a whole began the same process with marijuana and Mexicans.

Hearings Were Fraught With Racism

Throughout the entire discussion on marijuana at the time of its initial criminalization, the hearings and media featured lie after lie, filled with racism. These included claims that if men of color consumed marijuana, they would become violent and then solicit sex from the white women.

The Role of Anslinger

Narcotics Commissioner Harry Anslinger announcing raids in large U.S. cities aimed at crippling the narcotics traffic in New York on Jan. 4, 1958.

The previously mentioned Harry J. Anslinger, who was the US Federal Bureau of Narcotics’ head, played a very crucial rule in the criminalization of marijuana. There is widespread agreement that he was one of several driving forces behind the move to make cannabis illegal, although there are some variations in speculation on his specific reasons.

He was the commissioner of the FBN for 32 years. He additionally was a United States Representative for the United Nations Narcotics Commission for two years. Before these roles, he was the Department of Prohibition head in Washington, D.C.

Those who have researched Anslinger indicate that his fight for the prohibition of cannabis began when alcohol prohibition became a thing of the past in 1933. Prior to this, reports indicate that Anslinger had indicated he did not have a problem with cannabis, due to its lack of making others violent or hurting anyone. Johann Hari, who wrote a book about Anslinger and his role in the war on drugs, indicated that this changed when Anslinger realized he was the leader of a large department that did not have many responsibilities.

This led to a quick transition in Anslinger’s remarks regarding cannabis use. He began arguing that it would send users into a rage that is delirious before giving them erotic hallucinations and dreams. He even argued that using cannabis would eventually result in insanity. Over the years, Anslinger was quoted many times assaying ridiculous things about cannabis and those who use it, including racist remarks.

Anslinger used very limited evidence against marijuana at his disposal to support his points. This included the case of Victor Licata, a Florida boy who used an ax to kill his family and was allegedly high on cannabis, and the fact that one doctor of 30 consulted by Anslinger agreed that cannabis was dangerous.

The Controlled Substances Act

Years later, the original Marijuana Tax Act of 1937 was declared unconstitutional. However, the Controlled Substances Act during the 1970s replaced it. This act created various schedules or classes of drugs, organizing them based on the potential for a user to become addicted and their dangers.

When the Controlled Substances Act was released, cannabis is a Schedule I drug, which is the most restrictive category. This category is limited to drugs with high potentials for addiction, a complete lack of safety, and no accepted medical uses. This was supposed to be a placeholder until a report commissioned by President Nixon would make the final recommendation.

The Shafer Commission

Despite the claims that the report would be followed, it was not. The report was known as the Shafer Commission, and it indicated that marijuana should not be classified as a Schedule I drug. Furthermore, the commission even expressed doubt that it should be illegal at all. Despite the findings of the commission, Nixon ignored them and kept marijuana as a Schedule I drug.

Prohibition in Other Countries

The United States is far from the only country to ever ban the use of marijuana, with many countries following a similar timeline. Of course, the laws currently and have always varied between countries. Following the International Opium Convention in 1925, most countries made cannabis illegal. This convention was the follow-up to the first one at The Hague in the Netherlands in 1912.

The 1912 convention was the first treaty for international drug control. It focused mostly on the growth in the use and trade of opium, although cocaine was also discussed. This treaty included the signatures of the United States, Germany, France, China, the United Kingdom, the Netherlands, Japan, Siam, Russia, Persia, and Portugal. The 1925 convention was when the United States, China, and Egypt suggested adding a prohibition against hashish.

From there, a sub-committee at the convention suggested the expansion of the text to also prohibit trading, selling, and producing hashish as well as other cannabis-derived products. At the same time, it proposed restricting Indian hemp’s use for medical and scientific purposes. Some countries, including India, objected on the grounds of religious and social customs.

The Single Convention on Narcotic Drugs replaced the convention in 1961. This was the first international treaty that officially prohibited cannabis. It also provided the World Health Organization and the Commission on Narcotic Drugs the power to change the schedules of drugs.

The Move Towards Legalization

The road towards legalization of marijuana took its first major step in 1996 when California approved medical marijuana. The plant spent just 59 years being illegal in that state, a very small amount of time in comparison to its thousands of years of common use and legalization.

Today’s Arguments

The debate regarding the legalization of marijuana continues today. Opponents do not feel that there is enough evidence to support the use of medical marijuana and still employ scare tactics. Proponents of legalization argue that for thousands of years, humans used marijuana without any problems and point to the early scientific research that shows promise.

For now, more and more states in the United States seem to be legalizing marijuana every year, some only for medicinal purposes and some for recreational or medicinal use.

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