Does Cannabis Cure Cancer? These 9 Studies Say It Does

The capability of cannabis to influence cancer cells is probably the single most important medical aspect of this plant, as the number of people afflicted by this illness is constantly on the rise, with no signs of slowing down.

In this article, we’ll be examining:

  • How cancer occurs
  • Treatment methods (and their major strengths and disadvantages)
  • Current use of medicinal cannabis for cancer patients
  • Possible uses of cannabis against this disease in the near future
  • Groundbreaking scientific studies on this subject
  • Story of Rick Simpson and his cancer fighting oil

This is a complicated subject so let’s not waste any more time

The cannabis-cancer connection is in the endocannabinoid system

In countries and states where it’s currently legal, medical cannabis is used for alleviating symptoms that accompany classic cancer therapy methods, such as chemotherapy, radiation therapy and surgery.

Side effects of these treatment methods include chronic pain, fatigue, depression, sleep disorders, anxiety, nausea and loss of appetite.

Cannabis is already established as an alternative treatment method for a majority of these conditions, but scientists have recently uncovered that it also has the capacity to influence the behavior of cancer cells, the mechanism of which we’ll cover in later on in the article.

Before we go any further, I’d like to explain how exactly cannabis affects the body.

Unlike other substances, molecules from cannabis use a unique biochemical pathway in our bodies that reacts to phytocannabinoids which are found solely in cannabis. The prefix phyto means that these compounds are plant-based.

We usually refer to phytocannabinoids as just cannabinoids, but this shortening in actually unjustful because the human body (more precisely the mammalian body), also creates its own cannabinoids.

These internal cannabinoids are called endocannabinoids, and they play a capital role in the functioning of our organism.

The unique pathway that both endocannabinoids and phytocannabinoids use is called the endocannabinoid system, or the ECS.

This system was discovered by the Israeli scientist Raphael Mechoulam in the 90’s, and he and his team were also responsible for synthesizing the most abundant cannabinoid in cannabis, tetrahydrocannabinol — THC.

What Mechoulam found was that our body has a vast network of cellular receptors and activators, which are located in the most important parts of the body, such as the brain, spinal cord, vital organs, the gut, and even in our reproductive organs.

What’s unique about the endocannabinoid system is that its receptors can only be activated by cannabinoids, either from our body – by endocannabinoids, or from cannabis – by phytocannabinoids.

What’s even more fascinating is the actual function of the ECS.

Once activated by cannabinoids, the endocannabinoid system can perform an extremely wide number of operations, all of which are designed to serve a single purpose, and that is to keep our body in a state of harmonious balance.

This equilibrium of interconnected collections of cells, organs and tissues that the endocrine, lymphatic, nervous, digestive, muscular, respiratory, urinary and reproductive systems comprise of is called the homeostasis.

Even though these systems all have a different purpose and seemingly act separate from one another, they are indeed connected as they are all immensely important for a healthy functioning of our body.

The endocannabinoid system is a network of cell receptors and activators which are “designed” to help restore the balance to any of these systems, in the event that they fall out of it.

I find it somewhat puzzling that the entire scientific world was completely unaware of the existence of the ECS for such a long period of time, but when we consider how deviously cannabis got outlawed in 1937, this doesn’t really come as a surprise.

The federal ban on cannabis in America which is on power to this day still classifies it a class 1 narcotic, which means that on a federal level this plant doesn’t have any medical potential, even though numerous US states have legalized the recreational and medical use of cannabis.

It also implies that it has a high potential for both abuse and addiction, which are accusations that have been disproven by confirming that a recreational user can only become dependant on cannabis.

Dependency is several times less intense than addiction, and with the frequent use of alcohol, or heavy narcotics like opioids, both physical and mental addictions are practically guaranteed.

The biggest downside of the late discovery of endocannabinoids, phytocannabinoids and the endocannabinoid system is that we still don’t understand a great deal about how they function, but luckily what we understand so far definitely shows that cannabis has an astonishing impact on our health.

The similarity between our internal molecules — the endocannabinoids — and the molecular compounds from cannabis — the phytocannabinoids — could be understood that we were meant to use this plant as a tool to better our health, both physical and mental.

Before we start talking about all the scientific breakthroughs and discoveries regarding cancer and cannabis, we should first touch upon the regular cancer treatment techniques, and elaborate on their advantages and disadvantages.

In order to do that, we have to cover how normal cells become cancerous and why this happens in the first place, but also why we are experiencing such an increase in the number of patients suffering from this illness on a global scale.

How cancer starts, grows and spreads

A normal cell becomes cancerous when specific mutations in its genes prevent it from normally reacting to signals that control cellular growth and division which is called proliferation, and programmed cell death—apoptosis.

These mutations within the cell can be triggered by a wide range of negative stimulants, which include smoking, mostly because of the carbon monoxide and tar being released from the combustion of tobacco, but also from the combustion of cannabis.

Because of this, vaping both cannabis and tobacco is a much safer and healthier option, if you could ever put the word “healthy” in the same sentence as “tobacco”.

Bad diet choices, which include too much processed meats, hormones and antibiotics from regular meats, pesticides from non-organic fruits and vegetables, greasy foods, too much processed sugar, issues with obesity, excessive consumption of alcohol, and infrequent physical activity also contribute to the creation of cancer.

Some sources suggest that artificial sweeteners and genetically modified foods can also be responsible for creating cancer.

Besides the things we pretty much do to ourselves, the mutation of a normal cell into a cancerous one can also be caused by pollutants from the environment, infections such as HIV, hepatitis B and C, Epstein-Barr virus, but also various forms of radiation like exposure to ionizing radiation, and also excessive exposure to sunlight, which is another form of radiation.

Inherited genetic defects are also a variable, but only make up 5% to 10% of cancers worldwide.

All these factors, pollutants and negative stimulants basically throw specific parts of our organism out of harmony, which causes the detrimental changes is the genes of only one cell in our body to occur.

This singular reprogrammed malicious cell then start duplicating (proliferating) much faster than regular cells usually do, and even is even able to avoid cell suicide (apoptosis), because of the mutations in its genes.

The endocannabinoid system is an important part of our body’s defense mechanism against disharmony, and because of this phytocannabinoids from cannabis are such an effective tool against cancer.

How cancer cell works?

In a normal cell, hundreds of different genes collectively control the processes of cell division (or proliferation), but the genes are also responsible for the auto-destruction of a cell, which is also called apoptosis, or programmed cell “suicide”.

Apoptosis happens when a cell realises it’s either too old and should be destroyed, or if it’s defected and because of this shouldn’t exist any longer.

A healthy cell becomes cancerous either from exposure to radiation, pollutants, carcinogens, or from any other way that destabilizes our internal balance to such extent that the genes of the cell permanently change.

Once transformed, this cell will divide in a much faster rate then a normal healthy cell does. The cancerous cell will also become capable of avoiding genetic apoptosis, which would normally be bound to happen as that cell has numerous mutated genetic abnormalities.

Because of this our immune system is unable to fight this disease by itself, and requires outside help in order to defeat it.

How benign tumors become malignant?

A collection of the self-replicated cancerous cells is a tumor, and most of them remain enclosed within the borders of a specific tissue in our body. These are called benign tumors.

Some of these tumors have a potential to become malignant, if they’re allowed to grow uninterrupted. Once they are malignant, they become more powerful and gain the capacity to break through the boundaries of tissues by the secretion of the enzyme protease.

This allows them to spread across the body by invading neighboring tissues, using the bloodstream and the lymphatic system as a means of transportation. Once they reach new tissues, they continue with the proliferation, creating secondary tumors on these sites.

This stage of cancer cells is called metastasis, which literally translates to “new place”, but luckily not all cancer cells have the ability to metastasize.

Now that we’re acquainted with the basic principles of how a normal cells becomes cancerous and other important mechanisms of this illness, we can move on to the classical methods of treating cancer.

Conventional cannabis treatment methods


Surgery is the most frequent method for solid and isolated cancer, and usually attempts to remove the entire cancerous mass.

Lymph nodes of the affected area are also usually removed along with the tumors, and for some types of cancer, this technique is enough to alleviate the threat in its entirety.

Radiation therapy

The use of controlled and shaped beams of ionizing radiation is designed to target specific genes of cancerous tissues, and by doing so, it promotes apoptosis, or cell death. As I’ve previously mentioned, large quantities of ionizing radiation can induce cancer, but in these controlled amounts it is also used for fighting this disease.

Radiation beams greatly affect healthy tissues which they must pass through to get to the cancer, so to avoid afflicting it as much as possible the x-ray beams are fired from multiple different angles, which lessens the negative effects on healthy tissues, and maximizes the attack on tumor sites.

Radiation therapy is mostly combined with chemotherapy or surgery (or both), and for some cancer types it’s the sole treatment method, such as neck and head cancers. Different kinds of cancer react differently to this therapy.


Chemotherapy is the usage of specific cytotoxic or anti-neoplastic drugs in order to attack and destroy cancer cells that usually proliferate much more rapidly than other healthy cells.

There is a vast variety of drugs that act as chemotherapeutic agents, that includes broad groups of medicines such as alkylating agents and antimetabolites.

Another form of chemotherapy is targeted therapy, which uses molecular characteristics in order to differentiate between healthy and cancerous tissues.

It is used either alone (for leukemia), or in combination with surgery, where chemotherapy is administered to diminish the size of an otherwise inoperable tumor so it can be surgically removed from the body.

The biggest limitation to chemotherapy is its toxicity on healthy cells and tissues, meaning it needs to be frequently halted so the healthy parts of the body can recuperate from its toxic effects.

How cannabis cures cancer

Cannabis has already proven its potential as an effective palliative aid for lessening the negative effects of standard anticancer therapies, which can include pain, nausea, loss of appetite, insomnia, fatigue, depression and anxiety.

It is an especially much safer and healthier option for pain, where the pharmaceutical options such as opioids create severe side effects and addiction.

But in the last decade or so scientists have slowly started uncovering that cannabis also possesses qualities which make it a potential medicine not just for relieving side effects of cancer treatment, but also as an actual cure for cancer.

Dr. Christine Sanchez from the Complutense University in Madrid has been on the forefront of antitumor cannabis research since the early 2000’s.

She also recognizes the vast area of effect of the ECS, stating that:

“We now know that the endocannabinoid system regulates a lot of biological functions such as appetite, food intake, motor function, reproduction and many others and that is why the plant has such a wide therapeutic potential”

Dr. Sanchez also corroborates the difference between using cannabinoids and chemotherapy saying:

“One of the advantages of cannabinoid-based medicines would be that they target specifically tumor cells. They don’t have any toxic effect on normal non-tumoral cells. This is an advantage with respect to standard chemotherapy that targets basically everything.”

The mechanisms which cannabis uses for fighting cancer include:

  • Inhibition of cell proliferation (cell division)
  • Causing apoptosis (cell suicide / cell death)
  • Blocking of blood vessels which cancers depend on to grow
  • Inhibiting the ability of certain tumors to metastasize

Research studies on the anticancer effects of cannabis

Studies compiled by the National Cancer Institute

Numerous cancer-related preclinical studies were conducted to observe the possible positive effects of cannabinoids on humans.

Various research performed on mice showed that the benefits of phytocannabinoids from cannabis on cancer were multiple and included the induction of apoptosis, proliferation lessening and halting of the blood vessels that tumors require to grow.

As I previously mentioned, the endocannabinoid system is present in all mammals, and its main function is to restore the balance (homeostasis) of any of the vital systems within the mammalian body.

So even though there truly is a great evolutionary difference between mice and humans, especially regarding the complexity of these vital systems, we share the exact same animal cells (eukaryotes), and we also share the endocannabinoid system.

This means that, on a cellular level, we’re not so different from other mammals.

Laboratory evidence shows that cannabinoids destroy malicious cancer cells, while leaving healthy cells unharmed.

In regards to hepatocellular carcinoma, or liver cancer, tetrahydrocannabinol (THC) showed the ability to both damage, and to cause apoptosis to these type of cancer cells. (1)

The 2007 study from Harvard Medical School showed that THC positively influences the metastasis of highly aggressive EGF (epidermal growth factor) lung cancers by lessening the focal adhesion complex, which is essential for malignant tumor migration. (2)

THC also effects breast cancer cells cycle, which is the process which controls cell fate. Through the activation of CB2 receptors, tetrahydrocannabinol halts the proliferation of cancer cells by the induction of apoptosis. It was also noticed that healthy cells are completely unharmed with the introduction of THC. (3)

On the other hand, the phytocannabinoid cannabidiol (CBD) showed the ability to kill cancer-cells in estrogen receptor positive, and estrogen receptor negative breast cancer. (4)

Another group of studies examined the effects of cannabinoids on glioma tumor models and showed that THC and CBD cause cell suicide while leaving healthy cells completely unharmed. (5)

A lab study which researched the effects of CBD on human glioma cells showed that in combination with chemotherapy, cannabidiol increased the effectiveness of the chemo, as it increased the volume of death of cancerous cells, while at the same time protecting healthy cells. (6)

California Pacific Medical Center

Researchers from the institute in San Francisco performed several in vitro and animal studies the effects of cannabidiol on metastatic breast cancer, and found that CBD acts as a powerful anti cancer tool, which functions in three different ways. (7)

The first area of action involves the instigation of apoptosis (cell death), the other is the interference of communication between cancer cells, and the third area of action involves the changing the genes of terminal metastasis’, by shutting the growth receptors which are located in each individual cancerous cell.

International Journal of Oncology

This study showed that the use of only phytocannabinoids produces anticancer effects. (8)

Scientists behind this research also found that cannabinoids also play off each other (the so called entourage effect, where the various phytocannabinoids from the cannabis plant have a more potent and wider beneficial effect when applied together, in comparison when they are used apart), observed in vitro in leukemia cancer cells.

They observed the effects of paired cannabinoids on human cells in cell line models, and came to a conclusion that cannabinoids show anticancer characteristics by their own, but currently gave the best results in combination with anti-leukemia pharmaceuticals like vincristine and cytarabine.

The team added to the importance of the “entourage effect” of using both THC and CBD combined, revealing that the synergic effect is much greater in these instances.

They also specified that the timing is also very important to maximize the apoptosis (cell-death, also called cell-suicide) induction, and using cannabinoids after chemo provides much better results.

“Our results suggest that when certain cannabinoids are paired together, the resulting product can be combined synergistically with common anti-leukaemia drugs allowing the dose of the cytotoxic agents to be dramatically reduced yet still remain efficacious.”

The Journal of Urology

This study was analyzing the effects of both cannabis and cigarettes on bladder cancer. The team behind the research evaluated 39,222 men from the California men’s health study cohort (which is a multiethnic cohort created primarily to study prostate cancer), more precisely the South California Kaiser Permanente region of the CMHS.

Questionnaires were collected during the years 2002 and 2003, from participants who’s age ranged from 46 to 69. They included data about cannabis and cigarette use, and using cancer data from electronic health records excluded the 354 participants who already had bladder cancer, and Cox models were used to analyze the data.

From 39,222 men, 14,977 reported cannabis use, 21,700 reported tobacco use, and 10,027 reported both.

During the follow up study, 144 bladder cancers were identified, and naturally tobacco use was connected with a greater risk of cancer creation, while cannabis use was inversely connected, meaning cannabis use greatly diminished the probability of cancer development.

The team also noticed that more frequent cannabis users had lesser chance of developing bladder, unlike consumers who only tried it for a couple of times. (9)

This research wasn’t examining how cannabis protected the users, but it directly coincides with the other studies who deal with the exact mechanisms of action of cannabis against cancer.

Another essential piece of this puzzle is the oil which was first discovered by Rick Simpson, and is usually abbreviated as RSO, or Rick Simpson Oil.

Rick Simpson and his cancer fighting oil

Rick Simpson oil

Rick is a fellow Canadian from Nova Scotia, and he first became acquainted with cannabis after a serious injury in 1997. Doctors prescribed him with heavy opioid-based narcotics which didn’t alleviate the headaches and pain he experienced, but also had some serious adverse effects on his state of mind and general well being.

After watching an episode of David Suzuki’s Nature of Things about medical cannabis, he realized that could be a viable treatment for issues.

He was rejected multiple times by the authorities, so he found a way to purchase pot illegally.  With cannabis, he was able to completely stop using the pain medication that were causing so much harm to him.

The plot thickened when Rick got basal skin carcinoma, and after a failed surgical procedure to remove the tumor, the infected area of his skin was even worse than before the surgery.

He heard that cannabis possesses powerful anti-cancer traits, so he attempted to create an oil which could be used topically. He used only the flowers (or buds) of the plant, and 99% alcohol as a solvent. The end result was an oil which was very dense and packed with cannabinoids.

In just 96 hours of applying the oil several times a day, the cancerous area on his skin was gone. Rick tried to inform the hospital and various other institutions about his discovery, but was shunned out everywhere he went.

Disgusted by the lack of interest from the proper channels, he continued to make his high potency oil, and started giving it to people in his community for a wide array of issues and disorders, including cancer.

He even made a great documentary about his findings, and you can watch it and read the entire story in greater depth in our article about Rick Simpson.

All of this was going on in the early 2000’s when official cannabis research was extremely limited, but now that we understand the exact mechanisms cannabis uses to fight cancer cells, using highly concentrated oil instead of flowers seems like a far better options, because it still contains all the cannabinoids, but the amount which can be ingested via oil is far greater than with vaping, smoking or edibles.

Rick says that the oil made by his recipe (you can find the recipe in this article), is 90% pure cannabinoids, unlike flowers that can contain maximally around 20%.

This large quantity can potentially activate our endocannabinoid system to a much greater extent than any other form of consumption.

This increased dosage could be of great service against cancerous cells, but what’s worrying is that the use of such oil is strictly forbidden in all the countries and states that have medical cannabis legalized; even though when all the alcohol evaporates, the oil contains only plant material, and absolutely nothing else.


  1. Vara D, Salazar M, Olea-Herrero N, Guzmán M, Velasco G, Díaz-Laviada I; Anti-tumoral action of cannabinoids on hepatocellular carcinoma: role of AMPK-dependent activation of autophagy; April 2011; 1099-111
  2. Preet A, Ganju RK, Groopman JE; Delta9-Tetrahydrocannabinol inhibits epithelial growth factor-induced lung cancer cell migration in vitro as well as its growth and metastasis in vivo; January 2008; 339-46
  3. Caffarel MM, Sarrió D, Palacios J, Guzmán M, Sánchez C; Delta9-tetrahydrocannabinol inhibits cell cycle progression in human breast cancer cells through Cdc2 regulation; July 2006; 6615-21
  4. Daniel A. Ladin, Eman Soliman, LaToya Griffin, Rukiyah Van Dross; Preclinical and Clinical Assessment of Cannabinoids as Anti-Cancer Agents; October 2016; 7: 361
  5. Claudia A. Dumitru, I. Erol Sandalcioglu, Meliha Karsak; Cannabinoids in Glioblastoma Therapy: New Applications for Old Drugs; May 2018
  6. Vaccani A, Massi P, Colombo A, Rubino T, Parolaro D; Cannabidiol inhibits human glioma cell migration through a cannabinoid receptor-independent mechanism; April 2005; 1032-6
  7. Sean D. McAllister, Ryuichi Murase, Rigel T. Christian, Darryl Lau, Anne J. Zielinski, Juanita Allison, Carolina Almanza, Arash Pakdel, Jasmine Lee, Chandani Limbad, Yong Liu, Robert J. Debs, Dan H. Moore, and Pierre-Yves Desprez; Pathways mediating the effects of cannabidiol on the reduction of breast cancer cell proliferation, invasion, and metastasis; August 2011; 37-47
  8. Katherine A. Scott, Angus G. Dalgleish, Wai M. Liu; Anticancer effects of phytocannabinoids used with chemotherapy in leukaemia cells can be improved by altering the sequence of their administration; May 2017; 369-377
  9. Anil Thomas, Lauren Wallner, Virginia Quinn, Jeff Slezak, Gary Chien, Steven Jacobsen; Association between cannabis use and risk of bladder cancer: Results from the Men’s Health study; April 2013; e527
Categories Health

A passionate cannabis enthusiast, Marco mainly writes about cannabis culture and basics. Intensely skeptical about the establishment and a firm believer in critical thinking.

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