[Note: Callie Blackwell has commented after the post. Although I can’t agree with her conclusion that Deryn’s story is strong evidence that cannabis played a vital role in his recovery from bone marrow failure, she did make one good point, specifically that she never claimed that cannabis cured Deryn’s two cancers and that I shouldn’t have represented the excerpt to her book that way. She has a point. Although she clearly portrays cannabis as having been vital to her son’s seemingly miraculous recovery, to her it was because it somehow helped rescue the failing bone marrow transplant, not because it cured his cancer. Because I strive for accuracy in what I write and don’t even want to give the wrong impression stating facts, I have edited this post to remove any passage that said (or sounded as though it were saying) that Ms. Blackwell ever claimed that cannabis cured her son’s cancers. Mea culpa. Unfortunately, I doubt that the UK media will be so quick to stop representing Deryn’s story as proof that cannabis can cure cancer.]

In this book, Callie Blackwell states that cannabis oil cured her son of two cancers. But did it?

In this book, Callie Blackwell states that cannabis oil saved her son’s life when his bone marrow transplant appeared to be failing. But did it?

It’s been a while since I’ve written about the burgeoning business of selling marijuana as a cure for whatever ails you. As I’ve written before, there exists a mystical faith that is very much like herbalism that marijuana is a magical plant that can cure, well, almost anything, including cancer, glaucoma, autism, ADHD, and many other conditions, when in fact the evidence is rather shaky for most, if not all, of these claims. Regarding cancer, the usual claim is not that smoking marijuana cures the disease, but rather that cannabis oil isolated from marijuana cures cancer, a claim that Rick Simpson has profited from after claiming to have cured his skin cancer with cannabis oil in 2003.

Over the years, I’ve examined a number of “cannabis cures cancer” (or, truth be told, “cannabis cures” this or that condition) testimonials (e.g., Stephanie LaRue’s story). Like most alternative cancer cure testimonials, when you take a closer look, inevitably the case being made that it was the cannabis oil (or whatever derivative from marijuana was used) cured the cancer (or saved the patient’s life after complications of therapy) is nowhere near as convincing as the advocates making the testimonial claim. Usually, there is another explanation for how well the patient is doing and/or the link between starting cannabis oil and clinical improvement is not nearly as convincing as it seems on the surface. As with the case of the belief that vaccines cause autism, human beings mistakenly attribute correlation to causation. Add to that a dash of confirmation bias, something we human beings all suffer from, and it’s very easy to come to develop an unshakable belief in a post hoc ergo propter hoc fallacy in which something they observed or did before something else happened must have caused that something else to happen, be it vaccines “causing” autism or cannabis “curing” cancer.

I bring this up because there is a new “cannabis cures” testimonial going around the UK that was brought to my attention yesterday. It was about a boy named Deryn Blackwell, who beat leukemia and the very rare Langerhans sarcoma through multiple bone marrow transplants (BMT). The cannabis comes in during his last BMT, when his mother gave him cannabis oil to relieve his symptoms as his transplant appeared to be failing and was overjoyed when her son recovered after having been in hospice for over a month. Her story portrays cannabis oil as being responsible for bringing Deryn back from the brink of death. Predictably, the British tabloid media is portraying his story as a “cannabis cures cancer” story, even though, even taken at face value, it is not. I had already started a post on another topic when I saw this, and it grabbed my attention to the point where I abandoned what I was writing before to take a look at this testimonial. On the surface, it is a very convincing testimonial, which is why I decided, as Seth Myers would put it, to take a closer look.

The story of Deryn Blackwell, as told in the media

Deryn Blackwell is a 17-year-old boy whose story appeared in The Daily Mail over the weekend in an article entitled “I gave my little boy CANNABIS to help cure his cancer: Mother reveals how her teenage son who was given days to live made a miracle recovery when she gave him the drug behind his doctors’ backs.” (As an aside, besides its being a tabloid rag, it’s always irritated me how The Daily Mail loves ridiculously long headlines.) Other papers featured basically the same story with long similarly long headlines like “‘I GAVE MY BOY CANNABIS’ Mum reveals she gave her cancer-stricken son CANNABIS in bid to ease his pain… and now he’s made a miracle recovery.” Basically, Deryn’s story was all over the UK press over the weekend. The Daily Mail story is an excerpt from a forthcoming book (of course) chronicling Deryn’s battle with cancer entitled The Boy In 7 Billion, by Callie Blackwell with Karen Hockney, to be released on April 6. The description of the book reads:

The powerful and moving true story of a remarkable relationship and a tenacious fight for survival. Callie reveals her son’s struggle through the physical and mental torment of battling cancer against impossible odds, and the truth behind her son’s ‘miraculous recovery’ that she has held secret for years.

And it’s true. Deryn’s story is indeed remarkable, as you will see. The “secret” that Callie Blackwell has never revealed—until now!—is that it was cannabis that saved her boy when he was on the brink of death due to a failing bone marrow transplant. But was it? Let’s take a look at that excerpt. It starts out with this heart-rending description of Deryn as he got sicker:

The pain was getting worse. The tips of my son Deryn’s fingers were hard and black from a superbug infection. His nails were peeling away and any remaining live flesh was covered in weeping sores.

Every day, he begged me: ‘Please tell them to cut my hand off, Mum. I can’t take this any more.’

Deryn was nauseous and, worse, had become addicted to his anti-sickness drugs. He was allowed a dose every seven to eight hours but within an hour of being given some, he would press the buzzer to call the nurses back in.

What mother wouldn’t be utterly distraught watching her son suffer like this? What mother wouldn’t start to consider things that she normally wouldn’t, if only she could ease her son’s suffering. So Callie Blackwell did this:

Deryn had suffered enough. In 2010, when he was just ten years old, he had been diagnosed with leukaemia.

Eighteen months later, he was told he had a secondary cancer, the extremely rare Langerhans cell sarcoma. Only 50 cases have ever been recorded and only five people in the world currently have it. But no one had ever been found to have the two cancers combined, making Deryn unique. One boy in seven billion people.

By 2013, after nearly four years of hospital treatment, it seemed that the only thing left for him were opiate drugs to ease the pain as he reached the end of his life.

Like any mother would be, I was desperate to find something to alleviate his suffering.

I spent hour after hour researching on the internet, and that’s where I came across reports of a substance called Bedrocan, a cannabis-based painkiller that wasn’t available in the UK. Surely Bedrocan had to be a better option than mind-numbing morphine?

But the doctor told me that while it was effective, it had not been tested on children and she couldn’t prescribe it.

So Simon and Callie Blackwell, in an effort to ease their son’s suffering, sought out cannabis. Simon nobly took responsibility for obtaining some marijuana, using the rationale that if anyone were to go to jail for this he wanted it to be him and didn’t want Callie to be away from their son. The two of them did what most people who’ve decided to use alternative treatments do and read extensively on the Internet, where they learned to make cannabis extract suitable for a vaporizer pen using a rice cooker and vegetable glycerin, noting that in 2013, when they first decided to use cannabis:

Back at the hospital, meanwhile, our son’s latest bone marrow transplant had failed. Staff were giving up on him. It seemed Deryn’s death was a done deal and now all we could do was wait until he drew his final breath. If there was no improvement in two weeks, he would be placed in palliative care.

So what happened? Callie Blackwell went through with her plan. She brought her son the vapor pen:

Deryn sucked on the pen, breathed in and blew out a massive cloud of vapour – and we frantically waved our hands around trying to disperse it, although there wasn’t the smell of cannabis. It smelt more like popcorn. After ten minutes, Deryn said that the pain had decreased a little and he felt more relaxed – the words we had been longing to hear.

Alas, his condition continued to worsen. By December 2013, Deryn had moved out of hospital and into a hospice, where he planned his own funeral. His bravery attracted national attention and some of his favourite celebrities, including Paul Hollywood, Pauline Quirk and Linda Robson came to meet him.

I note that, here, despite Ms. Blackwell having started to sneak a cannabis vapor pen to her son for an unclear number of times, her son continued to deteriorate, and the vapor pen was only providing him with modest relief from the pain. He went to hospice, as far as I can reconstruct, two weeks after his mother started to sneak him puffs of cannabis. This is hardly the sort of “cannabis saved my child” story that sounds promising, at least not to this point.

Further deterioration…and then a “miracle”

What happened next is that, as Deryn’s condition continued to deteriorate during the two weeks after Callie Blackwell started to give him cannabis oil. Because he complained that he didn’t want any more morphine because it made him “feel like I’m not here,” she wanted to provide better relief and started wondering whether she could achieve a higher dose of cannabis by giving it to him orally. In actuality, she was almost certainly providing him a higher dose through the vapor pen, but she nonetheless decided to try. So on New Year’s Eve in 2013, roughly five weeks by my reckoning after she started sneaking her son cannabis oil by vapor, she tried it:

I was sitting next to him, a nightly vigil, and held his hand. Once again, the situation seemed quite desperate. What would happen, I wondered, if I gave Deryn a small amount of golden cannabis tincture directly in his mouth? The vaporiser had brought him some relief but could a higher dose have better results?

I took a small, empty syringe from the medicine cupboard in the hospice and quickly checked that there was no one outside. It was New Year’s Eve so staff levels were minimal. I drew up 5ml of the honey-like substance, which had a sweet, floral flavour.

Still sobbing uncontrollably, Deryn opened his mouth and I popped the syringe underneath his tongue. Deryn held it for a minute before swallowing. Half an hour passed. He was no longer having a panic attack. He looked peaceful. I asked him how he was feeling.

‘I feel relaxed,’ he told me. ‘I’m aware of everything. I just feel at peace, Mum. It’s beautiful.’

It’s a powerful story. No wonder it’s so compelling. Indeed, it’s an archetypical story, that of the parents who will go to any length to save their child from a deadly disease and succeed in doing so. Ms. Blackwell further relates that, after he swallowed the 5 ml of cannabis oil, he refused a dose of cyclizine, the antinausea drug upon which he had become dependent and that he virtually never refused. If there’s one part of this anecdote that puzzled me, it was the part about the cyclizine. Basically, cyclizine is painted as this powerful, addictive antinausea medicine when in reality it’s a histamine blocker and anticholinergic that is pretty well tolerated, with the usual adverse events of anticholinergic drugs, like dry mouth, and, less commonly, constipation, urinary retention, and double vision. Yet in this excerpt, the drug is painted as if it were a powerful, addictive opioid.

Be that as it may, the story certainly makes it sound as though 5 ml of cannabis oil beat cyclizine for nausea, although certainly there could be significant placebo effect here given his mother’s care and her giving him something new. Convinced it was working, Ms. Blackwell continued to give her son cannabis oil whenever he “felt a twinge somewhere.” Then, one evening:

One evening, I heard Deryn yell: ‘Mum – look!’ The bandage on his middle finger had worked its way loose and completely come off, showing his third finger – which had been blackened and dead – had now healed. How on earth had a child with no immune system and no way of fighting infection managed to heal himself after being off medication for more than three weeks?

I called Deryn’s team to tell them what had happened. Not one of them could give me any answers.

We knew his bone marrow wasn’t functioning and it was not scientifically possible for his wounds to heal. Deryn had spent months in isolation because a common cold could be fatal – yet, somehow, he had overcome three catastrophic infections.

Hundreds of people had been praying for Deryn, blessing him in their own ways. Was this a miracle?

Later that evening, the hospice doctor arrived. ‘We’re no longer sure Deryn is dying,’ she admitted.

The doctors were not sure whether or not the hospice was now the best place for us.

The story sure makes it seem like a miracle. One can only imagine the delight and relief, mingled with confusion and fear, that the Blackwells experienced, as their son, to whom they were preparing to say goodbye forever, made a sudden and unexpected recovery. Human nature being what it is, not surprisingly, Ms. Blackwell started looking for a cause for her son’s good fortune, and, human nature being what it is (and confirmation bias being what it is in all of us), she soon found one:

When we’d arrived four weeks earlier, he’d been given three days to live. Now here he was a month later, in far better health than when he’d left his hospital room. They had no idea how this was possible.

Then it dawned on me. Only one thing had changed since Deryn started to recover: the cannabis tincture. I couldn’t tell the doctors what we’d done.

Now, three years later, she’s revealing to the world what she did, and presenting it as a case of cannabis saving her son’s life. But did it? There is considerable reason to doubt. Those of you who are regular readers can probably identify the issues in this testimonial that make it less than convincing as evidence that cannabis salvaged Deryn’s failing bone marrow transplant. See if you can identify them before reading the next section.

The forthcoming book based on Deryn’s story aside, I’m very happy to report, Deryn returned to school and appears to be doing quite well now. Until now, his story popped up every so often as a human interest story in the UK press of a boy who beat what seemed like insurmountable odds to beat two different forms of cancer after “four failed bone marrow transplants,” while religious groups present him as a miracle. He even wants to study biochemistry, although he still suffers from sequelae of his disease:

“Deryn still struggles with mobility a bit and he gets very tired.

“But the main reason for going back was so he can develop emotionally and socially in that way teenagers, particularly boys, need to at that age.

“He has spent two years in a room by himself with just a nurse or me around, so it is good for him to just be normal for a while.”

Even after defeating cancer Deryn has had to confront other serious threats such as aplastic anaemia.

The family has also set up a charity, Do Everything, although currently the website is listed as Under Construction.

Did cannabis save Deryn’s life? It’s doubtful.

Remember how Ms. Blackwell discussed visits by celebrities to see Deryn around December 2013, as things looked very grim and doctors thought that Deryn’s final days were upon him? The beauty of his brief celebrity back then was that there are contemporaneous accounts of what was happening then that we can compare to Ms. Blackwell’s account today. It also turns out that Deryn and his family had a fairly robust social media presence (for 2013 back then, with a Twitter feed, Facebook page (which appears to be no longer there), and website. Although the website turns up as “Under Construction,” fortunately the almighty Wayback Machine lets us see what was on it as recently as 2015, which will be helpful in my discussion. Deryn’s Twitter feed has no Tweets since this one:

Perusing this Twitter feed and Ms. Blackwell’s recently set up author Twitter feed, I didn’t see any mention of cannabis until this flurry of weekend stories. For instance, the announcement of the book didn’t mention cannabis:

I found all this very curious, how Ms. Blackwell said absolutely nothing about cannabis until this weekend, even when her book release was announced and as she provided updates on her progress on her personal Twitter feed. Maybe the publisher made her keep it a secret. [Note: This is confirmed in the comments below.] Be that as it may, I found it instructive to fire up the almighty Wayback Machine and look at what the Do Everything Foundation website said. Helpfully, it provided a timeline, which was not nearly as clear in the book excerpt published by The Daily Mail. I think it’s worth posting the entire timeline from his last bone marrow transplant, which encompasses the time when Deryn went into hospice:

On 17th October 2013, his own cells failed because of extremely rare complications.

Thankfully Deryn had one more chance left, he had one more bag of his own cells.

The Dr’s gave Deryn more chemotherapy and on the 29th of October 2013, Deryn has his own and final bag of cells transplanted into his body.

Three days after the transplant, Deryn trapped his fingers and suffered TWO catastrophic infections in his hand.

He had Cellulitis and Herpes whitlow in his hand and he also had Klebsiella in his mouth, another catastrophic infection.

40 days after a bone marrow transplant, the Dr’s told us that it is highly unlikely that someone will graft if they haven’t already – after 50 days there is no way someone can graft.

In their experience, no one has ever grafted after 50 days.

On December 11th 2013, at day 46, we were moved to a hospice where it was expected that Deryn would die within a few days.

We were told that Deryn’s fourth and final transplant had in fact failed and there was nothing more they could do, it was believed that once they took away the life supporting drugs that Deryn would leave us very quickly.

Deryn had NO immune system and NO way to fight off even a simple cold.

After two Christmases, one New Year’s Eve and quite a few worrying moments, on day 78 Deryn’s bandages accidentally came off his fingers and he was – infection free!

Deryn continued to improve and he started to produce his own blood products.

On day 104 – Deryn officially engrafted!

Not one Dr can explain how Deryn fought off THREE catastrophic infections with NO immune system and then went on to engraft with what recent tests said was empty bone marrow!

On February 25th 2014, Deryn had his line removed from his chest and was officially ‘Off treatment.”

After coming to terms and accepting that he was going to die, Deryn was finding it harder to accept that maybe he wasn’t.

It all happened so quickly.

His future is still very uncertain and he is still poorly.


We are for the first time, starting to plan for a future with Deryn.

Thank you so much for visiting Deryn’s page and for reading his wonderful story.

** Miracles do happen and dreams can come true **

It’s not entirely clear exactly when Ms. Blackwell started giving Deryn cannabis oil, but it was clearly some time before he went into hospice on December 11, 2013. In the excerpt above, in the context of giving Deryn his first dose of cannabis, that the doctors would give him two weeks to improve and then, if he didn’t, move him to hospice, which suggests that she started dosing him in late November 2013. Then, by her own account, she didn’t start giving Deryn oral cannabis until New Year’s Eve 2013. Day 78 after his transplant would have made it January 15, 2014 when the bandages came off his fingers and revealed that he had healed much of his ulcers, and Day 104 would have been February 10, 2014.

One can see how this timeline might have led Ms. Blackwell to think that what had saved her son was the cannabis oil. She started giving him oral cannabis oil about two weeks before the ulcers on his hands unexpectedly healed. However, there are a number of reasons to doubt that it was the cannabis. For one thing, from this account we have no idea what strain of cannabis was used, making it difficult to estimate the cannabinoid content of the oil and therefore how much and what types of cannabinoids were in the actual oil Ms. Blackwell used. We don’t know the cannabis to oil ratio. We don’t even know the regularity of the dosing except that she gave it to her son “whenever he had a twinge.” Given the experimental data I’ve discussed before that shows that the various cannabinoids only have a modest anti-cancer effect, it’s hard to conclude that the doses Ms. Blackwell was giving her son were high enough to have had such a dramatic effect. For another thing, what Ms. Blackwell is claiming is not so much that “cannabis cured her son’s cancer,” but rather that cannabis somehow fired up his immune system so that it could fight off the infection and his cells could actually engraft after three times the length of time it normally takes. In reality, the evidence regarding cannabinoids and the immune system is mixed, with at least one study showing that they can suppress immune function. Indeed, cannabinoids are being studied more as a potential treatment for autoimmune diseases rather than as any sort of means of increasing immune cell engraftment. Basically, it’s not very plausible at all based on what we know about cannabis that Ms. Blackwell’s secret treatment of her son resulted in such a dramatic turnaround.

So what happened? Did cannabis really rescue Deryn Blackwell’s bone marrow transplant?

What probably happened is that Deryn Blackwell was a highly unusual case in which his last stem cell infusion took a far longer amount of time to engraft than the doctors at the hospital treating him had observed before. It just so happened that, as Deryn was deteriorating, his mother, anguished at watching him suffer and desperate to do anything possible to alleviate his suffering, decided to give vaporized cannabis oil a try to help his symptoms. Unfortunately, her son continued to deteriorate and entered hospice. She decided to give him the cannabis oil by mouth three weeks after he entered hospice, and it seemed to relieve his symptoms somewhat more effectively. Two weeks later, the “miracle” occurred, and the bandages fell off. Deryn’s rare and unexpected recovery, happily, manifested itself. The rest, as they say, is history.

Deryn’s recovery was unexpected, but unexpected and rare recoveries do occur in medicine. Given what we know about cannabis oil, its rather modest effect on cancer, and the tendencies of cannabinoids to be, if anything, immunosuppressive, it strains credulity on a strictly scientific basis to attribute Deryn’s turnaround on homemade cannabis oil. That’s not to say it’s impossible that cannabis oil was responsible for Deryn’s recovery, only that it’s incredibly improbable. Remember, we know a fair amount about cannabinoid activity against cancer and its activity in the immune system, and what we know doesn’t support the plausibility of Ms. Blackwell’s testimonial. However, as is the case with a lot of other alternative cancer cure testimonials, the all-too-human tendency to want to attribute cause, combined with the form of selective memory known as confirmation bias, which leads all of us to tend to remember what confirms our beliefs and to forget what does not, has led to a conclusion that is almost certainly not correct. Remember again, Ms. Blackwell seems not to remember the several weeks she was giving her son cannabis oil via vapor stick and he was continuing to deteriorate to the point of entering hospice. I repeat that again because it is important. This testimonial is almost certainly a case of confusing correlation with causation.

But what about this claim:

Yet there was a direct correlation between Deryn having the cannabis tincture and his improved blood counts. Whenever he didn’t have it, they dropped. It was enough hard evidence to suggest that cannabis tincture was playing a vital role in his recovery. I hadn’t imagined in my wildest dreams that it could have saved Deryn’s life.

Without very detailed record keeping in which Deryn’s counts were listed by date and then correlated contemporaneously with whether or not he was taking cannabis oil and at what dose, it’s impossible to support or refute this claim. It’s probably more confirmation bias.

Be happy for Deryn Blackwell, but be skeptical

Although I highly doubt that cannabis oil had anything to do with Deryn Blackwell’s “miraculous” recovery, I am very happy that he did recover. Nothing pains me more than seeing children die of diseases like cancer. I can also understand why Callie Blackwell and her husband Simon have come to believe that cannabis cured their son. They are human. They have all the cognitive quirks that lead humans to incorrect conclusions that we all have, and those tendencies are only magnified when it is someone they love deeply that is the object of their hopes and prayers. Confirmation bias is a very powerful thing indeed under these circumstances. Unfortunately, the timeline that I have been able to reconstruct is thin gruel indeed to support Ms. Blackwell’s belief that cannabis oil saved her son by somehow helping his immune cells engraft in his bone marrow.

Unfortunately, what I fear is that a combination of love for Deryn, confusing correlation with causation, and confirmation bias have led the Blackwells to become true believers on the order of Rick Simpson, but with an even more dramatic story in which cannabis is portrayed as having literally pulled their son back from the brink of death. Consider this. Deryn’s story is quite inspirational without the cannabis angle. Yet what excerpt did the publisher decide to release first as part of the book’s publicity campaign? Yes, it released the part describing how Callie Blackwell surreptitiously dosed her son with cannabis oil, and the Daily Mail and the rest of the UK tabloid media responded predictably with stories portraying Deryn Blackwell as proof that cannabis can cure cancer, even when his story shows nothing of the sort. Unfortunately, the narrative that is being spun has the potential to influence patients with cancer and parents to try unproven and quack treatments, like cannabis for cancer and who knows what else. In seeking to do good, I fear that the Blackwells could actually make it less likely that future Deryns actually survive their cancers. It saddens me to say it, but it has to be said.



Posted by David Gorski

Dr. Gorski's full information can be found here, along with information for patients. David H. Gorski, MD, PhD, FACS is a surgical oncologist at the Barbara Ann Karmanos Cancer Institute specializing in breast cancer surgery, where he also serves as the American College of Surgeons Committee on Cancer Liaison Physician as well as an Associate Professor of Surgery and member of the faculty of the Graduate Program in Cancer Biology at Wayne State University. If you are a potential patient and found this page through a Google search, please check out Dr. Gorski's biographical information, disclaimers regarding his writings, and notice to patients here.