What’s the difference between FECO and RSO?

Quick Summary

The main difference between FECO and RSO boils down to the solvent of choice used for extraction. The Original RSO oil recipe uses Naphtha, while the FECO recipes typically call for Ethanol. In my opinion Ethanol, which is drinkable alcohol, is a tad bit safer to use as a solvent if simply comparing the residuals. Other than the choice of solvents used, the actual difference between RSO vs. FECO is not very much at all.  Cannabinoids are extracted from cannabis plant material with a solvent. The solvent is then purged from the resulting mixture leaving the cannabinoids behind along with any other dissolved plant matter.


Two of the more popular cannabis oil extracts being popularized today are FECO (Full Extract Cannabis Oil) and RSO (Rick Simpson Oil) especially in the cancer treatment message boards.

A lot of well-meaning people will argue that each one of these is inherently better than the other but essentially, they are the same thing: Cannabinoids are extracted from cannabis plant material with a solvent.

The solvent is then purged from the resulting mixture leaving the cannabinoids behind along with any other dissolved plant matter. The only real difference between these two types of oils are the type of plant material used.


The main difference between FECO and RSO boils down to the solvent of choice. The original Rick Simpson Oil called for simmering quantities of cannabis using Naptha, a highly volatile hydrocarbon, as the solvent. Most FECO recipes call for a much less toxic solvent in the form of Ethanol.


You can obtain full extract cannabis oil from a variety of solvents. Improperly purging your solvent from your oil can leave those toxic solvents behind in your final product.  Purging some of those highly flammable solvents can also cause a fire or explosion, especially if done indoors.

Both the quality and quantity of the oil produced is directly dependent upon the material used. There seem to be two schools of thought when it comes to exactly what plant material to use.

Some pontificate that use every part of the plant should be used in your extraction process (FECO), while others argue that only the flowers/buds are the holy grail and the rest of the plant material just “waters down” the final product. The question is, which method will produce the most potent oil?


Suppose you were to prepare two extractions the same way using the extraction method of your choice. The first batch you make with a 1 ounce mixture of stems, leaves, and flower and the second batch you make from from 1 ounce of only cannabis flower. 

The first method will produce an oil with a much lower cannabinoid content than an oil made from only cannabis flower as there is little to no cannabinoids present in the stalks, stems and leaves of the cannabis plant.

Apart from the cannabinoids, terpenes and flavanoids, there aren’t any other noteworthy components residing in the soluble plant matter contained in a “full plant extraction” with any medical qualities.


The strain of cannabis plant you are using will also affect the outcome. Using a 15% THC strain will produce an oil with a much lower THC content than a top shelf strain boasting 30% THC. Alternatively, whether the flower used is Sativa or Indica dominant will also affect the outcome.

A nice potent oil made from a strong Sativa may not quite be what you are wanting to do before bedtime. If your treatment regimen requires it, use a strain that is high in both THC and CBD. There is a lot of room for customization here!


It is extremely important to know EXACTLY what you are getting! RSO, FECO and other cannabis extracts vary greatly in potency, especially if you are making it yourself. I have personally seen homemade variations testing anywhere from 19% to 62% THC in these final products depending on how they were made.

Based on those numbers, if you were following the generic online “protocol” of 60g over 90 days, that means your treatment cycle could contain anywhere from 11.5g to 37.2g of THC total. I’m sure you will agree that is a huge difference! So, what do you do?


The only way to guarantee consistency is to only use oils that have been tested for potency. If you are buying your oil from a dispensary, it should be labeled with the THC and CBD percentages. If you are making your own oils or your land does not require testing, then you MUST have a home THC test kit like the TCheck!

This amazing little machine tests your butter, coconut oil, olive oil, and alcohol based tinctures in less than 45 seconds. There is an additional accessory kit that you can purchase giving you the ability to test your flower or concentrates! Use the code Medible25 and receive $25 off your purchase!

Those looking to use FECO or RSO as a medicinal protocol should also read this article about the alternatives to FECO and RSO for cancer treatment.

*This post is strictly informational and does not offer any medical advice.

Author: Allan

8 thoughts on “What’s the difference between FECO and RSO?

  1. Rick Simpson Oil (RSO) is the real deal. My wife was diagnosed with stage 4 Breast cancer 7 years ago! Jumped through all the doctors’ hoops and ended up bed ridden and in a morphine haze. Life was depressing and torturous. We started RSO a few months ago and my wife is taking ZERO morphine and living her life like she has no cancer. We also just found out that 2 tumors in her liver have disappeared and the rest in her body have all shrunk. Honestly, RSO should not be an afterthought, it needs to be on the front lines of treatment. Even just seeing my wife off of Morphine has been a blessing that I will always be grateful for. (email removed)

      1. I am not sure what the laws are regarding Cannabis in the Philippines, so I cannot accurately answer that question. As mailing cannabis is pretty much illegal in every country, you would have to either source it locally or make it yourself if possible.

  2. I make mine with everclear, works great but I put it into gel caps because it honestly tastes like 💩💩💩 🤮🤮🤮

  3. Hello, where can I buy RSO? My sister is very sick with cancer in her bones and suffers so much pain. They have her on fentanyl patch 75 mg and takes morphine and still has pain. Please any information you can give me is greatly appreciated.

    1. Hi there,

      If you live in a state where cannabis is legal then visit your local Dispensary to get RSO or its equivalent. If you don’t live in a cannabis friendly area, I’m sorry but I cannot officially help you. Unofficially, our best chance is to take a drive to your closest legal neighbor, stock up and drive home. Know this: crossing state lines with cannabis is illegal, so weigh the options well before continuing. Good luck!

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