This page presents factual information about a protocol that is being used or searched by cancer patients. Our goal is accurate information and harm reduction, not endorsement. Always discuss with a qualified oncologist before considering any non-standard treatment.
RSO — Rick Simpson Oil
Also known as: Rick Simpson Oil, Cannabis Oil, Full-Spectrum Cannabis Extract, Phoenix Tears, FECO
RSO is a thick, dark cannabis extract made by soaking cannabis plant material in a solvent (typically naphtha or isopropyl alcohol) and then evaporating the solvent. Named after Canadian Rick Simpson, who claimed in 2003 that he cured his own basal cell carcinoma by applying homemade cannabis oil topically. RSO is typically very high in THC (60–90%) with variable CBD content, unlike medical CBD products.
What Proponents Claim
Proponents claim RSO cures cancer by inducing apoptosis (programmed cell death) in tumour cells, stopping tumour growth, and even causing complete remission — with no harm to healthy cells. Rick Simpson claims to have helped thousands of cancer patients achieve remission. The protocol typically involves escalating oral doses of RSO over 90 days (targeting 60 grams total). Some also apply it topically to skin cancers.
What the Science Actually Shows
Verdict: Plausible but Unproven
This is the most scientifically nuanced disputed protocol. The preclinical evidence is real and cannot be dismissed: THC, CBD, and other cannabinoids do induce apoptosis in multiple cancer cell lines in vitro, inhibit tumour angiogenesis in animal models, and reduce tumour growth in some rodent studies. The U.S. National Cancer Institute explicitly acknowledges cannabinoids have been shown to 'kill cancer cells in the laboratory' and that they 'may help treat the symptoms of cancer or the side effects of cancer treatment.' However — and this is critical — there are zero randomised clinical trials demonstrating RSO or high-dose THC oil cures human cancer. Case reports of apparent remission exist but cannot establish causation (patients may have had concurrent conventional treatment, or spontaneous remissions). GW Pharmaceuticals conducted Phase 1/2 trials of nabiximols (THC+CBD) in recurrent glioblastoma showing promise — this is legitimate research. The gap between 'kills cancer cells in a dish' and 'cures cancer in a human' is enormous and bridged only by RCTs — which do not yet exist for RSO.
Regulatory Stance
Cannabis remains Schedule I under the US Controlled Substances Act — federally illegal. FDA has not approved RSO or any cannabis preparation as a cancer treatment. FDA has approved synthetic THC (dronabinol/Marinol) and nabilone for chemotherapy-induced nausea and AIDS wasting. FDA also approved cannabidiol (Epidiolex) for epilepsy. The National Cancer Institute notes cannabinoids 'may have benefits in treating the symptoms of cancer' but does not endorse RSO as a tumour cure. Legal status varies widely by country and US state.
Known Risks
- High-dose THC causes significant psychoactive impairment — disorientation, anxiety, paranoia, especially in naive users starting the 90-day ramp-up
- CYP450 enzyme interactions: THC and CBD inhibit CYP3A4 and CYP2C9 — can significantly alter metabolism of many chemotherapy drugs (taxanes, vinca alkaloids, imatinib)
- Cardiovascular: THC increases heart rate, may precipitate tachycardia or arrhythmia
- Solvent residues: home-made RSO using naphtha or iso-propyl alcohol may contain toxic solvent residues if not properly purged
- Risk of abandoning conventional treatment in favour of RSO alone — the primary danger is delayed or foregone evidence-based treatment
- Psychosis risk in individuals with personal or family history of schizophrenia or psychotic disorders
- Legal risk — high-THC products are illegal in many jurisdictions
- Quality and potency varies enormously in unregulated products
Research & Regulatory References
iOnco does not endorse, recommend, or discourage any specific treatment decision. This information is for educational purposes only. If you are a cancer patient, please make treatment decisions in consultation with your oncologist and care team. Evidence-based conventional treatment should not be delayed or foregone based on information on this page.