Rick Simpson Oil: The Story Behind RSO

"Whatever you make of the medical claims, RSO is impossible to leave out of any honest history of modern cannabis advocacy."

Rick Simpson Oil — usually abbreviated to RSO — is one of those cannabis stories that almost everyone has heard, but few people have read carefully. This article is an attempt at the careful version. It is a piece of cultural and historical writing, not a medical document. Where Simpson and others have made therapeutic claims, we have attributed them clearly and we have not endorsed them. The Haze Cartel position is simple: cannabis-derived products with medical applications belong in the hands of clinicians and regulated medical programmes, not on the kitchen stove.

Who is Rick Simpson?

Rick Simpson is a Canadian engineer, born in 1949 in Nova Scotia. By his own account, he had no particular background in cannabis until the early 2000s, when, while researching alternative approaches to his own health concerns, he began producing a thick, dark, full-plant extract using cannabis flower and a solvent — most famously naphtha, though later iterations of the recipe more often use food-grade alcohols. He distributed the extract free of charge, primarily in his local community.

What "RSO" actually refers to

In the strictest sense, RSO refers to the specific extract Simpson described publicly: a high-strength, unrefined cannabis concentrate intended for oral use, usually administered in very small doses. In casual modern usage, "RSO" has become a generic name for any thick, full-spectrum cannabis extract sold or self-produced in a similar style, regardless of solvent or origin.

The 2008 documentary

Simpson's story reached a far wider audience through Run From The Cure, an independent documentary released in 2008. The film presented his own narrative and a series of patient testimonies. It also drew sharp criticism from medical and scientific commentators for the strength of its claims and the absence of controlled clinical evidence to support them.

Both the film and the response to it are now part of the historical record. RSO became a fixture of cannabis advocacy and a flashpoint in arguments about how cannabis should and should not be studied, regulated and spoken about.

How to read the medical claims

Simpson and a great many of his readers have attributed serious medical effects to RSO, including in relation to cancer. These claims are not supported by the kind of controlled clinical trial evidence that the medical community would normally require before treating a substance as a therapy. There is meaningful, ongoing research into specific cannabinoids and specific conditions — covered in our article on the endocannabinoid system — but that research is not the same thing as endorsing a homemade extract as a cure.

We include the medical claims in this archive because they are part of the historical story. We do not endorse them, and we strongly encourage anyone weighing cannabis-based treatment to speak to a doctor in a regulated medical setting. Our article on how medical cannabis returned to the UK covers the legal pathways that now exist.

The cultural legacy

Whatever you make of the specific claims, Rick Simpson Oil has had a real cultural impact. It helped frame the early-2000s argument that cannabis was a substance worth taking seriously as medicine. It contributed to the political momentum that led to reform in several jurisdictions. And it remains, today, one of the few cannabis topics that a non-smoker is likely to have heard of by name.

Where to go next

For the longer arc of cannabis as a subject of medicine, read Cannabis as Medicine: A Short History. For the science that helps explain why cannabinoids do anything at all, see The Discovery of the Endocannabinoid System.