An Open Letter to Rick Simpson by Dr. Franjo Grotenhermen


By Dr. Franjo Grotenhermen

Dear Rick Simpson,

You are probably the most well-known personality when it comes to the medical use of cannabis by cancer patients. Many desperate individuals, suffering from cancer and other serious maladies, put their trust in you and place great hope in your advice.

You are aware of this responsibility when you write in your book, Rick Simpson Oil – Nature’s Answer for Cancer, “I think anyone including myself, if put in a position of public trust, should expect to have their activities while working for the public watched very closely,” (Pos. 2528, Kindle). It is my conclusion, however, that you have not taken the proper measures commensurate with such great responsibility. I hope that in the future, you can do better.

I share your view when you write, “As I have stated many times, it is our watch and is our sacred responsibility to see that mankind will survive and prosper. Doctors will begin to follow the Hippocratic Oath and governments will begin to work for the greater good of the people. This is the only path we can follow which makes any sense and, if ignored, the destruction of the human race can be the only result,” (Pos. 2517, Kindle). And you continue, “My mission is simply to provide the truth to everyone possible, so together we can effect change,” (Pos. 3460, Kindle).

But I have to state that you are not taking many important facts into consideration – much to the detriment of people. You admit that you are “not a doctor” and do not “have the qualifications necessary to become one,” (pos. 1485, Kindle), but you take the liberty of exaggerating promises of healing that do not stand up to factual examination.

I want to clarify what one might interpret as overly harsh criticism, however, is inevitable, by six examples:

Lack of Knowledge

You write, “Decarboxylation occurs when the molecules within the oil have been rotated to the delta 9 position with the use of heat so they become more and medicinally active,” (Pos. 717, Kindle).

It is a fact, however, prior to decarboxylation, the substance is already delta-9-THC. With regard to the corresponding double bond in the THC molecule, nothing changes through the process. Decarboxylation means removal of carbon dioxide. This reaction converts the naturally present THC acid (THCA) in the plant into phenolic THC that is responsible for most of the therapeutic effects of delta-9-THC. I read on your website that you encourage to include plant-based foods in the diet, claiming that the proteins contained in plants possess cancer-fighting properties, as well. However, it is not proteins, but the phytochemicals, such as flavonoids, which may possess such properties.

Mistaken Beliefs

You write, “I think it’s of benefit to the patient for the oil to be administered as close as possible to a tumor or whatever is being treated. Therefore, if you have bowel problems, suppositories would likely work best, but if you have something like throat or stomach cancer, etc. I would ingest the oil by mouth,” (Pos. 1012, Kindle).

The truth is, that also in cases of abdominal carcinomas, cannabinoids reach the cancer through the body’s circulatory system. One should know some basic medicine, so as to not rely on beliefs, because they may turn out to be mistaken ones.

Confusing Amount and Concentration

You write, “By volume, it would be impossible for a hemp tincture to be as potent as pure oil. A patient could ingest their doses mixed with alcohol, but what good would taking this medication with alcohol do the patient?” (Pos. 1043, Kindle).

The truth is, that a diluted cannabis oil with a 5 percent THC content, ingested orally, has the identical pharmaceutical effect as a cannabis extract or cannabis oil with a THC content of 50 percent. This is because the effect is not based on concentration; it is based on the absolute amount. One milliliter of 50 percent cannabis extract contains the same amount of THCmillilitersilitres of a 5 percent extract, which is exactly 500 milligrams of THC. Only when applied externally does concentration play a role.

Missing Data

You write that, “On average, there is about one person in ten who will freely tell the world what had healed them but the majority of patients tend to remain more or less quiet … Since most people will not come forward, it makes my tasks that much harder and many will continue to die because those who have used these extracts refuse to discuss what they have witnessed,” (Pos. 1192, Kindle). And further, “Since 2003, I have provided these extracts to roughly 5000 people who were suffering with all types of medical problems. Many of these patients had several medical issues which needed attention but most were brought under control or cured with the use of this oil,” (Pos. 1377, Kindle).

You write yourself that only about one in ten patients treated by you offers feedback on the success of the treatment, and you complain that you do not hear back from most of them. Despite this, you undauntedly claim that all cancer patients, even those you never heard back from, were healed by the use of cannabis oil. Claims based on such limited data become completely absurd when contrasted with the fact that, depending on classification, there are between 100 and 1,000 types of cancer.

THC Fixation

You write that, “I always recommend high-grade oils for internal use in the treatment of serious conditions. A high-grade extract should contain THC levels in the range of 80-90% and produce an extremely sedative, yet euphoric effect when ingested. The higher the quality of the oil, the more pronounced will be its healing effects,” (Pos. 368, Kindle).

The truth is that besides THC, other cannabinoids possess cancer-inhibiting properties – in particular, CBD (cannabidiol). There are indications that in some types of tumors, CBD may play a more important role than THC. Moreover, there are strong indications that a combination of THC and CBD is more effective than THC alone, with regard to at least certain types of cancer. Among other factors, this can be of great importance when THC is insufficiently tolerated, and higher dosages are out of the question. In such cases, a treatment with high dosages of CBD can be attempted. You developed your theory 15 years ago when CBD was not yet in focus. However, our knowledge of the effectiveness of whole cannabis and cannabinoids in the treatment of cancer are of preliminary nature. And we must always take new data into consideration, offering our patients the most up to date advice and treatments possible.

Warning Against Effective Therapies

You write, “Unfortunately, many people who come to me have been badly damaged by the medical system with their chemo and radiation, etc. The damage such treatments cause have a lasting effect in people who have suffered these so-called treatments are the hardest to cure. But don’t despair, for even if you have been badly damaged, this oil still has a 70 to 80% success rate,” (Pos. 970, Kindle).

Now I arrive at a very serious issue. You recommend that all cancer patients avoid standard treatments because radiation therapy and chemotherapy both cause damage. Instead, all patients could be healed with your cannabis oil. We don’t know the actual success rate of your cannabis oil, and you can’t possibly know it either because you’ve had too little feedback from your clients. But we do know the success rates of standard therapies. In Germany, of the 500,000 individuals diagnosed with cancer each year, 280,000 are healed. This comes out to around 55%. As recently as 1980, two-thirds of all cancer patients succumbed to their ailment.

If the recovery rate from standard treatments continues to rise, and the rate of recovery for those treated with cannabis remains unknown, how many patients have died needlessly, following your advice?

And how many patients, who could have been healed, if they had received a combination of cannabinoids and conventional therapies, could have survived had they not solely relied on cannabis?

That you present things wrongly by not understanding chemistry, physiology, and medicine is not what I hold against you. One doesn’t necessarily need to understand all the details. However, this is a question of life and death, and such a serious issue, that you have to be accused of not living up to your responsibility and therefore your own aspirations.

This is about the wellbeing of individuals who turn to us. They have a right to the best possible and most recent information, as well the best possible advice. When it comes to medical treatment, especially when confronted with serious illness, it is not enough to treat patients by relying on good intentions and vehemently presenting a conviction.

I am convinced that your reputation among supporters would improve if you were able to revise and update your advice. I am convinced that cannabis and cannabinoid therapies are of value in the treatment of cancer. Let us address their potential with great care and consciousness!

Yours truly,

Franjo Grotenhermen

From the book: “Grotenhermen F. Cannabis gegen Krebs: Der Stand der Wissenschaft und praktische Folgerungen für die Therapie” [Cannabis against Cancer: The State of Science and Practical Conclusions for the Treatment]. Solothurn, Switzerland: Nachtschatten Verlag, 2017. With a preface by Dr Burkhard Hinz, Director of the Institute for Pharmacology and Toxicology, University of Rostock, Germany.


Franjo Grotenhermen, M.D., born in 1957, studied medicine at the University of Cologne. He runs a medical practice, mainly devoted to the medical use of cannabis and cannabinoids. Dr. Grotenhermen is the founder and chairman of the German Association for Cannabis as Medicine (ACM), founder and executive director of the International Association for Cannabinoid Medicines (IACM) ( and chairman of the Medical Cannabis Declaration (MCD). He is editor of the IACM-Bulletin, which is published bi-weekly in several languages and editor of the online journal CANNABINOIDS, published on the website of the IACM. He is a principal of the nova-Institute based near Cologne and author of many articles, books, and book chapters on the therapeutic potential, pharmacology, and toxicology of cannabinoids.

Photo courtesy of Allie Beckett

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  1. This is a great analysis of many of the issues surrounding Rick Simpson’s approach. His most important contribution was showing that high doses of cannabinoids administered continuously can have an anticancer effect in humans, but as this article demonstrates he’s far from perfect. This movement has come a long way since Rick and no one person or organization represents this now.

  2. Lawrence Goodwin on

    Thanks for sharing this important open letter,, and for so consistently featuring Allie Beckett’s beautiful cannabis images. They are always sweet complements to the text.

    The fact that this exact type of scientific research is STILL BEING BLOCKED in the United States is absolutely maddening. Years ago, I had surmised that at least one prominent medical professional would speak out against Rick Simpson’s well-publicized campaign to raise awareness about cannabis extracts. I’m glad to see it is Germany’s Dr. Grotenhermen, who wisely did so without ridiculing Simpson’s bold actions. The doctor also made clear that cannabis has enormous medical potential. Yet we must remember that a guy like Simpson is necessary only because, for 80 years, most doctors in America have been corrupted by Big Pharma largesse. Their unanimous silence is an egregious affront to ALL U.S. medical patients who could derive benefits from medical cannabis. Most doctors still cower before the federal government’s fraudulent Schedule I “marihuana” law, as if their predecessors (from the 1850s through the early 1940s) had not already commonly used cannabis extracts to treat many different medical problems. My point is that cannabis research should’ve NEVER BEEN BLOCKED. We’re talking here about an actual domestic crime against humanity that shows no signs of being stopped.

  3. An excellent article with which to end the year and enter 2018.

    Written to the lay man, by the renown doctor from Germany (check his credentials at the terminus of the article for more) it concisely rebuts in a respectful manner the works (and claims) of Rick Simpson, acknowledging the fact that Mr. Simpson is also a leader in his own field.

    This is a grand example of the movement for cannabis based medicine which now encompasses fully the practitioner, the researcher, the medical profession and of course the patient and consumer. It is a healthy interaction through the written word, and social media, that highlights just how far we have come and shows a bright future is possible,

    aka MamaBudz


  5. 55% are cured? What do you consider cured? Isn’t it true that most patients die as often from the “cure” as from the disease! What is the rate of relapse in the “cured” patients? Living an extra year or two is not a cure, its a prolongation of the agony of the disease and of the treatment. You quote no statistics at least because we all no how to twist them to our own agenda. I’ve read much, pro and con, scientific and anecdotal, and the truth seems to be your chemo and radiation keep one alive long enough to go through 2-4 cycles of “treatment” before you die, and that actual cures amount to about 3% not 55%. Modern “scientific” cancer medicine has become an extremely lucrative industry, yet no cure is on the horizon after all these years.

    And I’ve spoken with a number of cancer victims, ALL of whom stated that the treatment was much worse than the disease, to be continually poisoned in hopes of stopping a disease, that they wish they’d have just died of the disease, they felt no quality in their survival………

    Of course a doctor who gets paid a bonus of up to 60% of the cost the drugs, is going to defend their bank account! So yes, Rick makes some errors, and may be wrong in his estimates, but none who’ve taken his treatment have dies with sores in their mouths, unable to eat, unable to sleep, none vomit until their throats are destroyed by stomach acids, their bodies are not wracked with pain. If they died, at least they did not do so from the damage done by their treatment.
    When you have something better to offer than chemo and radiation, then we’ll listen to you. Do something useful, help us improve on what Rick has begun rather than waste time on criticism!

    • Here, here!! Les I agree with you.

      My own antidotes come from 6 years as a Paramedic in the military and civilian worlds. I have done many hours of volunteer care for cancer victims and help their families during attempted conventional treatments for several kinds of cancer that eventually killed most of the patients/victims of the disease. Very gruesome final days for most of them. One of my friends was bombarded with so much radiation for his brain cancer that it was nearly lethal with every treatment, with obvious radiation poisoning as a result. I think it comes down to a personal choice of what an individual is willing to tolerate. I had two friends that had the identical disease, non-cancerous brain tumor. One of them had the surgery and has lived, so far, an additional 35 years. The other chose not to have any surgery and died slowly over 7 years in a hospital bed at home. Its all a matter of choice.

      Having stated that, I salute the laymen pioneers like Rick Simpson and the pioneering doctor’s like Franjo Grotenhermen who have endured ridicule for their ideas and work. Doing anything in the public arena of opinion has a price. May God bless the both of them.

  6. I might add that without Rick Simpon Oil the further research sparked by his claims might never have happened

    The research that was able to counter Rick Simpson’s research also verified other aspects of his claims and fine tuned the regimens that do have success .

    He remains a Pioneer

  7. Yet Doc what do you think of a PAIN PATIENT like me to Replace the Rx Opiates with Cannabis only 13 yrs ago with THCA & THC. In a form of Olive oil medicine. That test at 130 mgs of THC & 195 mgs of THCA, in 1 table spoon of olive oil. When I use 3 tbsp I get real pain relief from the THCA & THC, my plant doesn’t have CBD as from the test says. So what is your knowledge of REPLACING the RX OPIATES for pain, with Cannabis strong medicine? I do 3 tbsp two times a day. I have a great treating Doctor since 1994 that once gave me my Rx Pills, to now write a Book on this. Medical Cannabis does work on Opiate Replacement…I know I did it 13 yrs ago.

  8. No one, including Rick Simpson has ever said that he was a Dr. He basically brought forth Cannabinoid Therapy. ALL OF these Dr’s are trying desperately to stop this therapy, because it will have a dramatic affect on there patient load, and there pocket. There is now many, MANY case studies coming from Isreal and other countries proving beyond a shadow of a doubt that cannabinoid therapy is extremely successful in many medical issues, and frankly, it is scaring the shit out of FDA, and doctors. I have my degree from CTU, Denver and I am heavily involved in Cannabinoid Therapy. Don’t but in to all of this B.S. coming from people who are tied into the FDA. They are spending Billions to try to stop this because the fact of the matter is, Dr’s could lose up to 50% of there patients who utilize Cannabinoid Therapy.

  9. these so called FDA approved drugs destroy my life. i took a drug name isotretinoin in 2007 in uk . i got neuropathy from that drug. after taking so many drugs specially ssri and snri . these drugs destroy my brain. some ANTI INFLAMMATORY gave me ulcer.some gave me itching.I took so called vitamin benfotiamine it gave me chronic cramps like pain in my thighs and arms. i came to know cannabis in start of 2017. i live in pakistan. here no body knows about cannabis and there is no proper dose. still i try after few try i took high dose and get high . it cure my itching, cure my burning feet and give me calmness of mind. i still have thigh pain because i dont have proper dose. i hope it will be cannabis is the best medication.and may god destroy these money hungry ignorant doctors. they can not do anything when u got side effects from drugs.

  10. “Decarboxylation means removal of carbon dioxide. This reaction converts the naturally present THC acid (THCA) in the plant into phenolic THC that is responsible for most of the therapeutic effects of delta-9-THC.”

    Actually, decarboxylation releases carboxyl (COOH) …de-CARBOXYL-ation.

    Maybe you can swing a break for Rick, given how you’re just as screwed up?

  11. No, decarboxylation releases CO2, the H stays in place of the COOH on the carbon chain. Franjo didn’t screw up, he knows more about this than perhaps anyone on the planet!

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