The History of Cannabis Prohibition: How We Got Here

A Plant with a Past

Cannabis has been cultivated by humans for thousands of years—used as medicine, fiber, and even a spiritual tool. But despite its long-standing relationship with civilization, cannabis has spent much of the modern era buried under layers of stigma, criminalization, and political agendas. So how did we go from widespread use to prohibition, and back again toward legalization?

Let’s break down the key moments that shaped the strange and winding journey of cannabis prohibition.

Ancient Roots to Early America

Cannabis traces back over 10,000 years to ancient China, where it was used for pain relief, digestive issues, and textile production. Its psychoactive properties were noted in ancient India and the Middle East, often in spiritual or medicinal contexts.

Fast forward to early America—hemp (a form of cannabis low in THC) was considered a vital crop. George Washington and Thomas Jefferson both grew it, and it was used to make rope, clothing, and paper.

Cannabis as medicine was also popular in 19th-century Western medicine, available in tinctures and prescribed for everything from migraines to insomnia.

The Rise of Anti-Cannabis Sentiment (Early 1900s)

At the turn of the 20th century, shifting political winds and cultural biases began painting cannabis in a new, negative light. After the Mexican Revolution (1910), Mexican immigrants brought recreational cannabis use to the U.S., especially in border states like Texas.

With xenophobia on the rise, authorities began associating cannabis with “dangerous” foreign cultures, crime, and social disorder. This was the beginning of racially charged narratives that would fuel prohibition.

Reefer Madness and the War on Cannabis (1930s–1970s)

In 1930, Harry Anslinger was appointed head of the newly formed Federal Bureau of Narcotics. He waged a public campaign to outlaw cannabis, using sensationalist media, racist propaganda, and exaggerated claims linking cannabis to insanity and violence.

In 1937, the Marihuana Tax Act effectively criminalized cannabis on a federal level, despite objections from the American Medical Association.

By the 1970s, the Nixon administration doubled down. Cannabis was classified as a Schedule I drug under the Controlled Substances Act—deemed highly addictive with “no accepted medical use,” right alongside heroin and LSD.

This kicked off the War on Drugs, which disproportionately targeted Black and Latino communities and led to mass incarceration.

Cracks in the System: Medical Cannabis and Reform (1990s–2000s)

By the late 20th century, public attitudes began to shift. In 1996, California became the first U.S. state to legalize medical marijuana. Scientific interest in cannabinoids like THC and CBD grew, especially for their potential to treat pain, epilepsy, and anxiety.

Activists, patients, and forward-thinking lawmakers began to challenge the prohibition narrative, supported by emerging research and real-world success stories.

Legalization Era: A Growing Green Wave

In the 2010s, the momentum shifted dramatically. Colorado and Washington became the first states to legalize recreational cannabis in 2012. Since then, over 20 states have followed suit, and public support for legalization has hit all-time highs.

Globally, Canada, Uruguay, Germany, and other countries have either legalized or decriminalized cannabis, signaling a dramatic shift in global policy.

So… Where Are We Now?

Despite federal prohibition in the U.S., cannabis is a multi-billion-dollar industry. Research is booming. Medical applications are expanding. Public opinion is overwhelmingly in favor of reform.

Still, full legalization remains tangled in politics, with thousands still incarcerated for cannabis offenses in places where it’s now legal to buy over the counter.

Cannabis prohibition wasn’t rooted in science—it was built on fear, racism, and politics. As society moves toward a more rational, informed approach, it’s essential to understand this history.

Legalization isn’t just about business—it’s about justice, health, and undoing nearly a century of misinformation.