Cannabis as Medicine: A Short History

"For most of recorded history, cannabis was a pharmacy item, not a banned substance. The ban is the historical anomaly."

Cannabis has been used as a medicine, in one form or another, for most of the period that we have written records of medicine at all. The modern argument over whether it should be a legitimate treatment is, in historical terms, unusually recent. This article does not make medical claims. It is a short tour of how physicians in different cultures and centuries have described the plant.

Ancient China and India

The earliest references to medicinal cannabis appear in Chinese pharmacological literature traditionally attributed to the mythic emperor Shen Nung, dating in its later compiled form to around the first century but drawing on much older oral traditions. The plant is described there as useful for a range of conditions including pain, menstrual difficulty and, perhaps surprisingly, absent-mindedness.

In India, the Ayurvedic tradition recorded cannabis preparations from at least the second millennium BCE, most famously bhang, a milk-and-spice drink still consumed during the festival of Holi. Indian medical texts described cannabis as a digestive aid, a sleep aid and a treatment for several specific complaints.

The Islamic Golden Age

Through the medieval Islamic medical tradition, cannabis appears in the work of physicians such as al-Razi and Ibn Sina. Hashish — the concentrated resin form — was discussed both medicinally and as a recreational substance, with all the cultural complexity that implies. The tradition was clear-eyed about both uses, and treated them as different problems.

Victorian Britain

Cannabis entered the modern British pharmacopoeia largely through the work of William O'Shaughnessy, an Irish physician who encountered Indian cannabis preparations while working as a surgeon for the East India Company. His 1839 paper introducing cannabis to European medicine described its use for pain, muscle spasm and convulsions, including in paediatric epilepsy.

Through the second half of the nineteenth century, tinctures of cannabis were sold across Britain by major pharmaceutical manufacturers. Queen Victoria's physician famously prescribed cannabis for menstrual pain. Prescriptions of this kind were not exotic — they were ordinary medicine, dispensed at ordinary chemists.

The decline

The early twentieth century brought a steady retreat. Cannabis preparations were difficult to standardise — a problem that pharmaceutical chemistry of the era was not yet equipped to solve — and the rise of injectable opioids and synthesised analgesics offered prescribers more predictable tools. International narcotics control regimes in the 1920s and 1930s placed cannabis in the same regulatory category as drugs with very different pharmacological profiles.

In the United States, the 1937 Marijuana Tax Act effectively ended medical prescription. In the United Kingdom, the equivalent practical end came with the 1971 Misuse of Drugs Act, which placed cannabis in a schedule with no recognised medical use. Almost overnight, a substance that had been in the pharmacopoeia for more than a century became invisible to medicine.

The return — briefly noted

The story of how cannabis has returned to formal medical use in the UK is told in a separate article: How Medical Cannabis Returned to the UK. The scientific underpinning for taking cannabinoids seriously again is told in The Discovery of the Endocannabinoid System.

A note on what this means

The long history of medicinal use is sometimes invoked as if it settled the modern question on its own. It does not. What it does establish is that the modern prohibition is the historical anomaly, not the medical use. That is a fact worth knowing when you read contemporary debate.