In 2003, a Canadian maintenance engineer named Rick Simpson applied a homemade cannabis concentrate to three cancerous growths on his arm, covered them with bandages, and waited. According to Simpson, the growths disappeared within days. What followed was not a peer-reviewed clinical trial or an FDA application — it was a grassroots movement that would make Rick Simpson Oil one of the most widely discussed, fiercely debated, and frequently replicated cannabis preparations in the world.

Two decades later, RSO occupies a complex space in the cannabis landscape. It is sold in licensed dispensaries in nearly every legal state, recommended by patient advocacy groups, discussed in oncology forums, and produced at home by thousands of people following instructions that Simpson himself published freely. The evidence base for its medical claims remains largely preclinical, but the demand is enormous and growing.

This guide covers the history, the extraction science, two proven methods for making cannabis oil at home, critical safety information, and evidence-based dosing protocols.

What Is RSO?

Rick Simpson Oil is a full-spectrum, whole-plant cannabis extract made using a solvent-based extraction process. Unlike isolated cannabinoid products (such as pure THC distillate or CBD isolate), RSO retains the full range of cannabinoids, terpenes, flavonoids, and other plant compounds present in the source material.

The result is a thick, dark, tar-like oil — usually nearly black in color — that is typically consumed orally rather than smoked. RSO is extremely potent, with THC concentrations commonly ranging from 60-90% depending on the starting material and extraction technique.

Key characteristics that distinguish RSO from other cannabis concentrates:

  • Full-spectrum profile: Contains THC, CBD, CBN, CBG, CBC, and dozens of other cannabinoids plus terpenes, rather than isolated compounds
  • Oral consumption: Designed to be eaten (on food or in capsules), not smoked or dabbed
  • High-volume dosing: The traditional RSO protocol calls for consuming up to 1 gram per day — far more than typical cannabis dosing
  • Whole-plant philosophy: The entire aerial portion of the plant (flowers, sugar leaves, and sometimes trim) is used, maximizing the breadth of the chemical profile

A Brief History

Rick Simpson’s story begins in 1997, when a workplace accident left him with chronic dizziness and tinnitus. After conventional treatments failed to provide relief, Simpson turned to cannabis following a documentary he watched about medical marijuana. His symptoms improved. When he was later diagnosed with basal cell carcinoma in 2003, Simpson — recalling a 1975 study from the Journal of the National Cancer Institute showing that THC reduced tumor growth in mice — decided to apply concentrated cannabis oil directly to his skin lesions.

Simpson claimed the cancerous spots healed. His physician, by his account, was unwilling to attribute the outcome to cannabis. Undeterred, Simpson began producing large quantities of the oil and distributing it free of charge to patients in his Nova Scotia community. Canadian authorities raided his property multiple times, and he was eventually charged with drug trafficking, possession, and cultivation — charges that were dropped after patients testified on his behalf.

Simpson published his extraction method online and in his 2013 book, encouraging anyone with access to cannabis to make the oil themselves. He never patented the process or attempted to commercialize it, which is part of why the name “Rick Simpson Oil” became a generic term rather than a branded product.

Extraction Method 1: Ethanol (The Traditional RSO Method)

This is the method Rick Simpson himself described and the most common approach for producing RSO at home. It uses food-grade ethanol (high-proof grain alcohol) as the solvent to strip cannabinoids and other compounds from the plant material.

What You Need

  • Cannabis: 1 ounce (28 grams) of dried, cured flower. Higher-quality starting material produces higher-quality oil. For medical use, many patients choose high-THC indica strains, though the optimal strain depends on the condition being targeted.
  • Solvent: 1 gallon (3.8 liters) of food-grade ethanol, minimum 190 proof. Everclear (190 proof) is the standard choice. Do not use isopropyl (rubbing) alcohol, methanol, or denatured alcohol — these contain toxic additives not meant for human consumption.
  • Equipment: Large glass bowl or stainless steel container, wooden spoon or silicone spatula, cheesecloth or fine mesh strainer, rice cooker or double boiler, silicone spatula, oral syringes for storage.
  • Safety equipment: Nitrile gloves, safety glasses, well-ventilated area (ideally outdoors).

Step-by-Step Process

Step 1 — Prepare the cannabis. Lightly break up the dried flower by hand. You do not need to grind it finely — in fact, a coarse break produces a cleaner extract because it prevents excessive chlorophyll extraction. Remove any stems or seeds.

Step 2 — First wash. Place the broken cannabis in a large glass bowl. Pour enough ethanol to completely submerge the material — typically about 500ml for one ounce. Using a wooden spoon, gently stir and press the plant material for 3-4 minutes. This first wash extracts the majority of the cannabinoids and terpenes from the outer trichome layer. The ethanol will turn dark green to amber.

Step 3 — Strain the first wash. Pour the ethanol through cheesecloth or a fine mesh strainer into a clean glass container. Squeeze the cheesecloth to extract as much liquid as possible. Set this liquid aside.

Step 4 — Second wash (optional). Some producers perform a second wash on the same plant material with fresh ethanol for an additional 3-4 minutes. The second wash extracts remaining cannabinoids but also pulls more chlorophyll and plant waxes, resulting in a darker, harsher-tasting oil. Whether to do a second wash depends on your priority: maximum yield versus maximum purity.

Step 5 — Evaporate the solvent. This is the most critical step from a safety perspective. The ethanol must be completely evaporated, leaving only the concentrated oil behind.

The traditional method uses a rice cooker: pour the strained ethanol solution into a rice cooker set to its lowest heat setting. As the ethanol evaporates, add more of the strained solution. The rice cooker’s built-in thermostat prevents the temperature from exceeding 210-230 degrees Fahrenheit (100-110 degrees Celsius), which is high enough to evaporate ethanol (boiling point: 173 degrees Fahrenheit / 78.3 degrees Celsius) but low enough to avoid significant cannabinoid degradation.

This step MUST be performed outdoors or in an extremely well-ventilated area. Ethanol vapor is highly flammable. See the safety section below.

Step 6 — Final purge. When the rice cooker’s contents have reduced to a small volume of thick, bubbling oil, transfer the oil to a small, oven-safe glass dish. Place it in an oven set to 200 degrees Fahrenheit (93 degrees Celsius) for 30-60 minutes to evaporate any remaining solvent. The oil is done when it stops producing small bubbles, indicating all ethanol has been purged.

Step 7 — Collect and store. While the oil is still warm and fluid, draw it into oral syringes (typically 1ml or 3ml syringes) for precise dosing and storage. RSO solidifies as it cools, becoming thick and tar-like. Stored in syringes in a cool, dark location, RSO can maintain its potency for 6-12 months or longer.

Expected Yield

One ounce (28 grams) of high-quality cannabis flower typically yields 3-5 grams of finished RSO. The exact yield depends on the THC content of the starting material, the efficiency of the extraction, and the number of washes performed. A 20% THC flower processed efficiently should yield oil testing in the 60-80% THC range.

Extraction Method 2: Coconut Oil Infusion (Solvent-Free)

For those uncomfortable with solvent-based extraction — or in jurisdictions where high-proof ethanol is difficult to obtain — coconut oil infusion provides a safer, simpler alternative. The result is less concentrated than traditional RSO but avoids any concerns about residual solvents.

What You Need

  • Cannabis: 7-14 grams of dried, cured flower (decarboxylated — see below)
  • Coconut oil: 1 cup (240ml) of organic, refined coconut oil. MCT oil works as well and stays liquid at room temperature.
  • Equipment: Oven and baking sheet (for decarboxylation), slow cooker or double boiler, cheesecloth, glass storage jars.

Step-by-Step Process

Step 1 — Decarboxylate the cannabis. Raw cannabis contains THCA, the non-psychoactive precursor to THC. Heat converts THCA to THC through a process called decarboxylation. Break the flower into small pieces, spread on a parchment-lined baking sheet, and bake at 240 degrees Fahrenheit (115 degrees Celsius) for 40 minutes. The cannabis should turn from green to a light golden-brown color.

This step is not necessary for ethanol RSO because the solvent evaporation process generates enough heat for decarboxylation. But for oil infusion, where temperatures never exceed the boiling point of water, decarboxylation must be done separately.

Step 2 — Combine and infuse. Place the decarboxylated cannabis and coconut oil in a slow cooker set to the lowest setting (around 160-180 degrees Fahrenheit / 70-82 degrees Celsius). Stir occasionally over 4-6 hours. The extended low-temperature infusion allows the fat-soluble cannabinoids to dissolve into the oil without significant degradation.

Alternatively, use a double boiler on the stovetop, maintaining a gentle simmer in the lower pot while the cannabis and oil sit in the upper pot. This gives you more precise temperature control but requires more active monitoring.

Step 3 — Strain and store. After the infusion period, strain the oil through cheesecloth into a clean glass jar. Squeeze thoroughly to extract all oil from the plant material. Discard the spent plant matter. Store the infused coconut oil in the refrigerator for up to 3 months or at room temperature (if using MCT oil) for up to 6 months.

Potency Comparison

Coconut oil infusion produces a much less concentrated product than ethanol RSO. A typical batch using 14 grams of 20% THC flower infused into 1 cup of coconut oil will contain roughly 2,800mg of THC total — approximately 12mg THC per milliliter. This is significantly less concentrated than ethanol RSO (which can contain 500-800mg THC per gram) but is much easier to dose accurately and gentler for beginners.

Critical Safety Warnings

Cannabis oil extraction, particularly the ethanol method, involves genuine hazards that have caused injuries, house fires, and explosions. These are not hypothetical risks.

Solvent Safety

Ethanol and all hydrocarbon solvents are extremely flammable. Evaporating a gallon of ethanol produces a large volume of highly flammable vapor that is heavier than air and will pool at floor level. A single spark — from a lighter, an electrical switch, a pilot light, or static electricity — can ignite these vapors with explosive force.

  • ALWAYS perform solvent evaporation outdoors. Not in a garage with the door open. Not next to a window. Outdoors, in open air, away from any structures.
  • NEVER use an open flame, gas stove, or any ignition source near evaporating solvents. The rice cooker method is popular specifically because rice cookers use enclosed electric heating elements.
  • NEVER use butane, propane, hexane, or naphtha for home extraction. These solvents are far more dangerous than ethanol and have been responsible for the majority of cannabis extraction explosions reported in news accounts. Open-blasting butane in a residential setting is extremely dangerous and illegal in most jurisdictions.
  • NEVER use isopropyl alcohol (rubbing alcohol) as a substitute for ethanol. Isopropyl alcohol contains toxic denaturants and produces oil that is not safe for human consumption.
  • Use a fan to disperse vapors if you must work in a semi-enclosed area. Direct the fan to blow vapors away from any ignition sources.

Dosing Safety

RSO is extraordinarily potent. A single gram of RSO can contain 600-900mg of THC — equivalent to 30-45 standard edible doses. Accidental overconsumption is common among beginners and can produce extreme anxiety, paranoia, racing heart rate, nausea, and incapacitation lasting 6-12 hours.

There is no documented case of a fatal cannabis overdose, but severe THC overconsumption is a genuinely unpleasant experience that sends thousands of people to emergency rooms annually. Treat RSO with the same dosing respect you would give any potent medication.

Cannabis extraction is illegal in many jurisdictions, even where cannabis possession and use is legal. Some states regulate extraction methods specifically — for example, banning hydrocarbon extraction (butane, propane) while permitting ethanol extraction. Know your local laws before proceeding. Possession of cannabis concentrate, even in states with legal flower, may carry different penalties or require different licensing.

Dosing Protocols

The Rick Simpson Protocol

Rick Simpson’s original protocol, designed for serious medical conditions, calls for a total of 60 grams of RSO consumed over a 90-day period, following a gradual escalation schedule:

  • Weeks 1-3: Start with a dose the size of half a grain of rice (approximately 5-10mg THC), taken 2-3 times daily. This is a very small amount — roughly a tiny dot on the end of a toothpick.
  • Weeks 3-5: Gradually double the dose every 4-5 days as tolerance builds. Most patients can increase without significant side effects if the escalation is slow.
  • Weeks 5-12: Continue increasing until reaching the target dose of approximately 1 gram per day (split into 2-3 doses). At this level, patients are consuming 600-900mg of THC daily — an enormous dose by any standard, and one that requires substantial tolerance.

The 90-day protocol assumes a total consumption of approximately 60 grams (60 one-gram syringes) of RSO. At dispensary prices of $30-60 per gram, the total cost ranges from $1,800 to $3,600 for the full protocol.

It must be stated clearly: this protocol has not been validated in clinical trials. The dosing schedule is based on Rick Simpson’s personal experience and the anecdotal reports of patients who followed it, not on controlled studies with standardized endpoints. The 60-gram figure and the 90-day timeline are not derived from pharmacokinetic data or dose-response curves.

Conservative Medical Dosing

For patients using RSO for symptom management rather than following the full Simpson protocol, a more conservative approach is appropriate:

  • Start: 5-10mg THC per dose (a very small amount of RSO, roughly the size of a quarter grain of rice)
  • Increase: Add 5mg per dose every 3-5 days as tolerated
  • Target: Find the minimum effective dose for symptom relief. For chronic pain, this might be 25-100mg per day. For sleep, 10-50mg taken before bed.
  • Timing: Take doses in the evening initially, as sedation and psychoactive effects will be significant at first. As tolerance develops, patients can add daytime doses.

Administration Methods

RSO is typically consumed in one of these ways:

  • Direct oral consumption: Squeeze the dose from the syringe onto a small piece of food (a cracker, a piece of bread) and eat it. RSO has a strong, bitter, plant-like taste that most people find unpleasant.
  • Capsules: Fill empty gelatin or vegetarian capsules with measured doses of RSO. This eliminates the taste issue and makes dosing more precise.
  • Sublingual: Place the dose under the tongue and hold for 60-90 seconds before swallowing. This allows some absorption through the sublingual mucosa, potentially producing faster onset (15-30 minutes vs. 1-2 hours for oral), though most of the dose will still be swallowed and processed through the digestive system.
  • Topical: Apply directly to skin over areas of localized pain or skin conditions. Topical application does not produce psychoactive effects because cannabinoids applied to the skin do not typically reach the bloodstream in significant quantities.

Medical Applications: What the Research Says

The medical claims surrounding RSO — particularly regarding cancer — are the subject of intense debate. Here is what the evidence actually shows.

Preclinical Evidence (Laboratory and Animal Studies)

The preclinical evidence for cannabinoid anti-cancer activity is genuinely promising. Hundreds of studies have demonstrated that THC, CBD, and other cannabinoids can kill cancer cells, inhibit tumor growth, and reduce metastasis in cell cultures and animal models. Key findings include:

  • A 2006 study in the British Journal of Pharmacology showed that THC induced apoptosis (programmed cell death) in glioma cells while leaving healthy cells relatively unaffected.
  • A 2014 study in Molecular Cancer Therapeutics found that the combination of THC and CBD enhanced the effectiveness of radiation therapy in glioma models.
  • A 2019 review in the Journal of the National Cancer Institute Monographs summarized evidence that cannabinoids can affect multiple cancer hallmarks, including cell proliferation, apoptosis, angiogenesis, and metastasis.

Clinical Evidence (Human Studies)

The clinical evidence is far more limited. As of 2026, there have been no large-scale, randomized controlled trials demonstrating that RSO or any cannabis preparation cures, treats, or prevents cancer in humans. The existing human data consists of:

  • Case reports: Individual patient stories describing tumor regression or symptom improvement following RSO use. These are valuable for generating hypotheses but cannot establish causation because of the absence of controls.
  • Small pilot studies: A 2021 pilot study published in Frontiers in Oncology involving 14 patients with high-grade glioma who received a combination of THC and CBD alongside standard treatment showed encouraging survival data, but the sample size was too small for definitive conclusions.
  • Symptom management evidence: There is strong clinical evidence that cannabis-based medicines are effective for chemotherapy-induced nausea and vomiting. Dronabinol (synthetic THC) and nabilone (a synthetic cannabinoid) are both FDA-approved for this indication.

Where Things Stand

The gap between preclinical promise and clinical proof remains wide. Killing cancer cells in a petri dish is a very different accomplishment than treating cancer in a living human being. Many compounds that show anti-cancer activity in vitro fail to work in clinical settings for reasons related to bioavailability, metabolism, immune system interactions, and tumor microenvironment complexity.

This does not mean RSO is ineffective — it means we do not yet have the evidence to know whether it is or is not. Patients considering RSO for serious medical conditions should discuss it with their oncologist or primary care physician and should never abandon proven conventional treatments in favor of unvalidated alternatives.

Making an Informed Decision

RSO and cannabis oil occupy a genuinely complex space — sitting at the intersection of promising preclinical science, passionate patient advocacy, regulatory uncertainty, and commercial interest. The extraction process itself is well-established and straightforward. The safety concerns are real but manageable with proper precautions. And the dosing protocols, while not clinically validated, have been followed by large numbers of patients who report meaningful benefits.

What matters most is approaching the subject with clear-eyed realism. The science is encouraging but incomplete. The anecdotal evidence is abundant but not a substitute for controlled clinical data. And the extraction process, while simple, demands genuine respect for the hazards involved.

For patients who have discussed cannabis with their healthcare providers and decided to proceed, the methods outlined here provide a reliable foundation for producing a consistent, full-spectrum cannabis oil at home. For everyone else, the growing availability of lab-tested RSO at licensed dispensaries offers a safer and more standardized alternative to home production.