Short Answer

No clinical trial has shown that cannabis RSO oil cures cancer in people. Research on THC and other cannabinoids against cancer is limited to laboratory work, animal studies, and a small number of human case reports and early trials. Some of those results are promising, but none prove that RSO shrinks tumors or extends life in humans. What cannabis products do have proof for is relief of certain treatment side effects, including chemotherapy-induced nausea and vomiting and appetite loss, through specific FDA-approved formulations. Anyone considering RSO should use it alongside, never instead of, standard cancer treatment.

read more

What RSO Is

RSO stands for Rick Simpson Oil, named after the Canadian man who popularized it in the mid-2000s. It is a full-extract cannabis oil made by soaking cannabis flower in a solvent such as ethanol or naphtha, then evaporating the solvent to leave a dark, thick resin. The result is a concentrate with very high THC content and a full range of plant compounds, including terpenes and other cannabinoids. Because it is a solvent extract, the quality of the purge matters. Residual solvent, pesticide, and heavy metal contamination are real concerns with homemade versions.

related article

Patients use RSO in several ways: swallowed as a dose on food or in a capsule, held under the tongue, applied to the skin, or, in some case reports, used as a suppository. In states with legal medical cannabis, RSO is sold as a concentrate, though the name is a brand-style term and not a regulated product category.

where to buy rso oil

What the Research Shows

Laboratory and animal studies

Test-tube studies show that THC, CBD, and other cannabinoids can kill cancer cells or slow their growth through pathways involving apoptosis, autophagy, and angiogenesis. Mouse studies have found tumor reduction in some cancer types when cannabinoids were delivered at the tumor site. These results matter for building hypotheses. They do not carry over to humans, because dosing, delivery, metabolism, and tumor biology differ.

rso oil dosage for pain

Human evidence

The human evidence is thin. A handful of small trials and case reports have looked at THC-rich extracts in recurrent glioblastoma, as an add-on to standard treatment. Results have been mixed, and the studies were not randomized or blinded, so no conclusion can be drawn from them. The National Cancer Institute states that cannabinoids have shown anticancer activity in laboratory and animal models but that human evidence is limited. Larger controlled trials are in planning or underway, and none have reported a survival benefit.

Treatment side effects

Here the evidence is stronger. Two synthetic THC drugs, dronabinol and nabilone, are FDA approved for chemotherapy-induced nausea and vomiting that has not responded to other antiemetics. Dronabinol is also approved for appetite and weight loss in AIDS patients. RSO is not an approved drug, but patients often report relief from nausea, appetite loss, pain, and sleep problems. Those reports are subjective and can be shaped by expectation.

Legal and Regulatory Status in the US

Cannabis remains illegal under federal law. Individual states allow medical or adult-use cannabis with their own rules on possession limits, product testing, and patient registration. No cannabis product is FDA approved to treat cancer, and the FDA has warned companies against making cancer cure claims. Buying from an unlicensed source carries legal risk and a higher chance of contaminated product.

Before You Start

RSO is a high-THC product with psychoactive effects and real interactions with prescription drugs. Take these steps before the first dose.

How People Use RSO Alongside Cancer Care

This is harm reduction guidance, not a prescription. Dosing schedules vary by product and person, and no standard dose exists for cancer.

  1. Agree with your clinician on a fixed schedule for any dose changes.
  2. Buy from a licensed dispensary that publishes third-party lab results for potency, pesticides, solvents, and heavy metals.
  3. Start with a dose the size of a half grain of dry rice, about 5 to 10 mg of THC.
  4. Take it with food to slow absorption.
  5. Wait at least two hours before taking any more.
  6. Hold that dose for two to three days before raising it.
  7. Increase in small steps if side effects stay manageable.
  8. Write down the time, the dose, and how you felt, so you can spot patterns.
  9. Keep the oil in a locked, labeled container away from children and pets.
  10. Stop and call your care team if you have chest pain, fainting, severe vomiting, or a panic reaction.

Risks and Drug Interactions

High doses of THC can cause anxiety, paranoia, racing heart, dizziness, dry mouth, red eyes, and impaired coordination. These effects are stronger in people who are new to cannabis and in older adults. Cannabis can interact with CYP450-metabolized drugs, changing blood levels of some chemotherapy agents, anticoagulants, anticonvulsants, and immunosuppressants. Heavy daily use carries a risk of dependence and, in some people, worsening anxiety or depression. Do not smoke or vape RSO. The oil is not made for inhalation and can injure the lungs.

Questions for Your Oncology Team