The Forgotten History of Cannabis in American Medicine

Medical cannabis is often framed as a modern development, a product of recent legalization efforts and contemporary scientific research. This perception overlooks a long and well-documented history in which cannabis was not only accepted but routinely prescribed by American physicians. For much of the nineteenth and early twentieth centuries, cannabis was considered a legitimate therapeutic substance, available through pharmacies and endorsed in medical textbooks. Its removal from mainstream medicine was not the result of new scientific discoveries proving it ineffective or dangerous, but rather a convergence of political pressure, racialized fear, regulatory overreach, and shifting pharmaceutical interests.

Understanding the forgotten history of cannabis in American medicine is essential for contextualizing today’s debates about its therapeutic value. It reveals how social narratives can override medical evidence and how regulatory frameworks can shape scientific inquiry itself. This history also helps explain why cannabis research lagged behind other therapeutic fields for decades and why misconceptions about the plant persist despite renewed medical interest.

Cannabis Before Modern America

Cannabis had an established medicinal reputation long before it entered American medical practice. Historical records document its therapeutic use in ancient China, India, and the Middle East, where it was applied for pain relief, inflammation, gastrointestinal issues, and neurological conditions. These traditions informed European medical knowledge during the colonial period, particularly through British medical literature developed during imperial expansion.

The bridge between Eastern medicinal use and Western clinical practice was largely built in the early nineteenth century. Irish physician William Brooke O’Shaughnessy, while working in India, conducted systematic observations of cannabis and documented its effects on patients suffering from conditions such as tetanus, cholera, and convulsions. His work introduced cannabis to Western medicine as a subject of scientific interest rather than folklore. His findings were published in respected medical journals and circulated widely among physicians in Europe and the United States, laying the groundwork for cannabis’s adoption in American medicine.

Cannabis Enters American Medical Practice

By the mid-1800s, cannabis had become a common component of American therapeutics. Physicians prescribed cannabis extracts and tinctures for a variety of conditions, including chronic pain, migraines, insomnia, muscle spasms, and menstrual discomfort. Unlike many medicines of the era, cannabis was viewed as relatively safe when properly administered, particularly compared to substances such as opium or mercury-based compounds that were also widely used.

Cannabis preparations were typically administered orally, often as alcohol-based tinctures that allowed for measured dosing. Medical journals of the period discussed its sedative, analgesic, and antispasmodic properties in clinical terms, reflecting its integration into standard practice rather than experimental use. Importantly, cannabis was not considered controversial or fringe. It was one of many botanical medicines employed by physicians trained in emerging scientific methodologies.

Cannabis in the United States Pharmacopeia

Perhaps the strongest evidence of cannabis’s legitimacy in American medicine is its inclusion in the United States Pharmacopeia. The USP serves as an official reference for drug standards and accepted medical substances in the United States. Cannabis was added to the USP in 1850, confirming its recognized therapeutic value at a national level.

For over ninety years, cannabis remained in the USP. During this time, it was recommended for conditions ranging from neuralgia and rheumatism to gastrointestinal disorders and nervous system ailments. Pharmaceutical companies manufactured standardized cannabis extracts to ensure consistency and reliability, addressing concerns about variability that sometimes affected botanical medicines.

Major pharmaceutical firms, including Parke-Davis and Eli Lilly, sold cannabis-based medicines through pharmacies across the country. Medical textbooks and physician guides referenced cannabis alongside other accepted treatments, and pharmacists were trained in its preparation and dispensing. Its removal from the Pharmacopeia would later symbolize not just regulatory change, but the erasure of cannabis from the institutional memory of American medicine.

Early Twentieth-Century Shifts in Attitude

The early twentieth century marked a turning point in American attitudes toward cannabis. This shift was not driven by new clinical evidence demonstrating harm, but by broader social and political forces. The Progressive Era saw increasing concern over drug use and a push for federal oversight of medicines, culminating in the Pure Food and Drug Act of 1906. While this law focused on labeling and safety rather than prohibition, it laid the foundation for more aggressive regulation.

At the same time, cannabis became entangled with xenophobic narratives. Recreational cannabis use among Mexican immigrants in the southwestern United States was sensationalized by media and politicians, who portrayed the plant as a foreign menace associated with crime and moral decay. These portrayals ignored cannabis’s long history as a medical substance and instead framed it as a social threat.

The Marihuana Tax Act of 1937

Federal policy reached a critical juncture with the passage of the Marihuana Tax Act of 1937. Rather than banning cannabis outright, the Act imposed prohibitive taxes and regulatory requirements on its production, distribution, and prescription. Physicians were required to complete extensive paperwork and pay fees to prescribe cannabis, creating legal risks that most were unwilling to accept.

The American Medical Association opposed the Act, arguing that it would interfere with medical practice and restrict access to a legitimate therapeutic substance. Despite this opposition, the Act passed and effectively ended medical cannabis use in the United States.

The Act also contributed to the decline of cannabis research. As legal barriers mounted, academic institutions and pharmaceutical companies shifted their focus away from cannabis toward substances that were easier to study and commercialize under emerging regulatory frameworks.

The LaGuardia Committee Report

In the midst of escalating anti-cannabis rhetoric, a notable scientific investigation challenged prevailing assumptions. In 1938, New York City Mayor Fiorello LaGuardia commissioned the New York Academy of Medicine to conduct a comprehensive study of cannabis use. The resulting report, published in 1944 as The Marihuana Problem in the City of New York, examined medical, social, and psychological data related to cannabis consumption.

The LaGuardia Committee found that many claims about cannabis were exaggerated or unsupported. It concluded that cannabis was not physically addictive, did not cause violent behavior, and was not a gateway to harder drugs. The report emphasized the lack of evidence linking cannabis use to serious social harm and directly contradicted federal narratives promoted by the Federal Bureau of Narcotics.

Despite its rigor, the report was largely dismissed by federal authorities and had little impact on national policy. Its findings were overshadowed by entrenched political agendas and the momentum of prohibition.

Removal from the U.S. Pharmacopeia

In 1942, cannabis was removed from the United States Pharmacopeia, formally stripping it of recognized medical status. This decision marked the end of cannabis as an accepted medicine in the United States. Without USP recognition, physicians no longer viewed cannabis as a legitimate treatment, and pharmacies ceased carrying cannabis-based medicines.

The removal was not based on new evidence demonstrating ineffectiveness or danger, but on regulatory and legal considerations stemming from the Marihuana Tax Act. As a result, cannabis vanished from medical education and practice, leaving subsequent generations of physicians unfamiliar with its therapeutic history.

The Controlled Substances Act and Research Suppression

Federal policy hardened further with the passage of the Controlled Substances Act in 1970. Cannabis was classified as a Schedule I substance, defined as having no accepted medical use and a high potential for abuse. This classification placed cannabis alongside heroin and severely restricted research opportunities.

The Schedule I designation created a paradox: cannabis could not be studied extensively because it was deemed to have no medical value, yet it was deemed to have no medical value because it could not be studied. Researchers faced significant bureaucratic hurdles, including limited access to research material and stringent approval processes.

But just today, President Donald Trump signed an executive order reclassifying cannabis as a Schedule III drug. While we don’t know for certain if this will be positive for the cannabis industry in the long run, it seems like it could be the start of some real research being done. Learn more about Trump and his views on cannabis.

State-Level Legalization and the Revival of Medical Cannabis

Medical cannabis re-entered public discourse in the late twentieth century through patient advocacy and state-level initiatives. In 1996, California passed the Compassionate Use Act, allowing patients with qualifying conditions to access cannabis with physician recommendation. This marked the first major legal recognition of medical cannabis in decades and challenged federal prohibition.

Other states followed, creating medical cannabis programs that allowed patients to use cannabis for conditions such as chronic pain, epilepsy, and multiple sclerosis. These programs revived interest in cannabis research and forced reconsideration of long-held assumptions about the plant.

How History Shapes Today’s Medical Cannabis Landscape

Today, medical cannabis occupies a complex legal and cultural space. While federal law remains restrictive, many states in USA have their own state cannabis laws and scientific research continues to uncover therapeutic potential in cannabinoids and terpenes. The historical record demonstrates that cannabis was once a respected medicine, marginalized not by science but by policy.

Reexamining this history provides valuable perspective on current debates. It highlights the importance of evidence-based policymaking and reminds us that medical consensus is shaped not only by data, but by social and political context.

The Enduring Impact of Cannabis on American Medicine

The forgotten history of cannabis in American medicine challenges the notion that medical cannabis is a recent invention. For nearly a century, cannabis was prescribed, studied, and sold as a legitimate therapeutic substance. Its removal from medicine was driven by fear, stigma, and regulatory pressure rather than scientific refutation.

As medical cannabis continues to gain acceptance, understanding this history is essential. It reveals how easily medical knowledge can be suppressed and how important it is to separate evidence from ideology when shaping healthcare policy.

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