Marijuana and Cancer

Separating fact from fiction: A look into the claims that cannabis can cure cancer and treat its symptoms and marijuana as a potential cause of lung cancer.
Last Updated: March 05, 2019

One of the most hotly-debated forms of cancer treatment is cannabis. Doing an internet search for “cannabis cancer” opens up a rabbit hole of websites, links and studies. It can be tough to sort out science-based evidence from anecdotal information. Is cannabis really a cancer wonder drug with the ability to shrink tumors into oblivion? Is cannabis really a helpful medication for the nausea and other side effects that often come as a result of conventional cancer treatments? Also, what about the risks of cannabis itself – does smoking marijuana cause cancer?

Studies on Marijuana and Cancer Cells

The most promising evidence in favor of marijuana for cancer treatment comes when cannabinoids, or the active ingredients in marijuana, are used in a laboratory setting. Studies have shown them to be potential anti-cancer agents. Specifically, scientists have discovered that cannabinoids prevent certain types of cancer cells from multiplying and developing new blood vessels. This means that cannabinoids may be a useful tool in inhibiting cancer cell growth.

THC and Cancer

In addition to these findings, however, some studies have shown that THC (tetrahydrocannabinol), one of the primary cannabinoids in marijuana, may inhibit the anti-tumor immune response in the body. Although THC also has anti-cancer effects, these additional findings are concerning as it means that it may also provide a favorable environment for some kinds of tumors to develop and grow.

CBD and Cancer

Next to THC, CBD (cannabidiol) is the cannabinoid found in highest concentrations. The same study that revealed THC’s anti-tumor activities also showed that CBD has tumor-regressive properties in addition to increasing apoptosis, or tumor cell death. Additional research into using CBD for cancer has shown that CBD prevents cancer cell growth through multiple mechanisms. While the world may be some time away from a CBD cancer treatment, these results are promising.

Cannabis Is Not Yet a Cure

Through continuing research, scientists are sorting out the meaning behind the results they’ve uncovered so far, but one thing is clear: while the chemicals in cannabis have been shown to be effective tumor fighters, marijuana itself has not yet been shown to be an effective cure.

While some studies have shown positive results in using cannabis-derived compounds in animals and cancer cells in petri dishes, more research is needed to figure out how this can translate into useful medical treatment. It’s important for patients to understand that the compounds used in these studies are not the same as ingesting or applying whole-plant marijuana or its concentrates. Furthermore, lab studies have not yet proven the cannabis-derived compounds to be as effective as conventional cancer treatments at actually curing the disease in human patients.

“More recently, scientists reported that THC and other cannabinoids such as CBD slow growth and/or cause death in certain types of cancer cells growing in laboratory dishes. Some animal studies also suggest certain cannabinoids may slow growth and reduce spread of some forms of cancer.

There have been some early clinical trials of cannabinoids in treating cancer in humans and more studies are planned. While the studies so far have shown that cannabinoids can be safe in treating cancer, they do not show that they help control or cure the disease.

Relying on marijuana alone as treatment while avoiding or delaying conventional medical care for cancer may have serious health consequences.”

In summary, while there are studies suggesting that certain isolated and concentrated substances within cannabis may have anti-tumor effects when used in a laboratory setting, this doesn’t mean that cannabis cures cancer. Science has yet to turn this research into a real-world cure.

These early studies are being touted by some as a reason to abandon conventional cancer treatments and opt to treat the disease using substances such as marijuana and hemp oil. There is no evidence to suggest that smoking or otherwise ingesting cannabis or hemp oil is useful as a cancer cure in humans. It can, however, be used as a supplement to conventional treatments.

Watch: Could cannabis oil cure cancer? BBC News

Medical Marijuana for Cancer-Related Symptoms

Just because cannabis isn’t a cure, however, doesn’t meant that it isn’t a useful medication for cancer patients. There is plenty of evidence that it can be used to supplement conventional cancer treatments. In fact, some of the biggest health benefits of marijuana are its ability to combat symptoms like pain, nausea, anxiety, and insomnia.

Chemotherapy often comes with a whole host of unpleasant side effects – and with those side effects come an entire list of medications. Marijuana can work as a replacement for many of these.


Many cancer patients experience pain, either as a symptom of the disease or as a side effect of their ongoing treatment. In addition to this, chemotherapy can cause neuropathic pain. Many people choose cannabis for pain in order to forgo conventional pain medications in favor of a safer, more natural alternative. Marijuana can be used in place of strong opioid painkillers over a long period of time without concerns about side effects such as constipation and addiction.

Nausea and Loss of Appetite

Another common side effect of chemotherapy is nausea and vomiting. With this comes a steep drop in appetite – something that can weaken a patient and cause them to lose weight. Many people find that consuming medical marijuana for cancer helps combat both nausea and suppressed appetite – eliminating the need to take a separate medication for each condition.

In an interview with Newsweek, Dr. Donald Abrams said that marijuana “is the only anti-nausea medicine that increases appetite.” It’s so effective that a synthetic THC drug called dronabinol has been approved for nausea, vomiting, and appetite stimulation in cancer patients and those with AIDS.

Anxiety and Depression

Cancer patients are often prescribed antidepressants to combat the emotional side of battling the disease. Most of these medications cause unwanted side effects such as upset stomach, drowsiness, or increased agitation. The cannabinoids in marijuana have been proven to alleviate anxiety while elevating mood.


Patients also find relief from using marijuana for cancer-related insomnia, whether their sleeplessness is due to discomfort or anxiety. Studies have shown that given at the proper dosage, THC is effective at helping people fall asleep faster. It also reduces sleep interruptions throughout the night. Again, proper dosages are important; in studies where the THC dosage was as high as 30 milligrams, patients reported feeling hung over the next morning. When the dose was reduced to 20 milligrams, patients experienced no morning-after effects. This sets marijuana apart from most sleep aids that cause grogginess and disorientation in the first few hours after waking up.

Marijuana and Lung Cancer

With all of the focus on cannabis and cancer, some people are left wondering if using cannabis for any purpose – even if it’s medicinal – carries risks. What about marijuana and lung cancer? Does marijuana cause cancer?

Some studies have found that just like tobacco smoking, long-term marijuana smoking does increase the risk of lung cancer. Others have found no connection between marijuana and lung cancer (likely due to the fact that marijuana smokers consume smaller amounts of cannabis flower than tobacco smokers do when they consume tobacco).

However, a wide variety of consumption methods means that anyone who is concerned about the potential risks needn’t smoke marijuana. Cannabis and its concentrates can be consumed via vaping, edible treats, oils, sprays, and topical rubs. These alternatives to smoking are popular with recreational users as well as people taking medical marijuana for cancer.

Marijuana/Cancer FAQ

Does marijuana kill cancer cells?

Studies have shown that certain cannabinoids, or the active ingredients in marijuana – have anti-tumor properties. This doesn’t mean that marijuana cures cancer, however; these studies have been limited to laboratory environments and have not yet been translated into real-world cancer treatments.

What about CBD and cancer?

Studies show that CBD has anti-tumor properties; however, this knowledge has yet to be turned into an actual CBD cancer treatment. CBD has many other health benefits; it’s an anti-inflammatory, sedative, and antidepressant. With a doctor’s approval, it could be a helpful supplement to traditional cancer therapies.

Does marijuana cure cancer?

Not yet. While it’s promising to see studies showing that cannabinoids like THC and CBD can prevent tumor cells from growing and multiplying, isolating cannabinoids and using them in a lab isn’t the same as ingesting cannabis and its concentrates.

Does smoking marijuana cause cancer?

There is contradictory evidence regarding the lung cancer risk associated with smoking marijuana over the long term. Can marijuana cause cancer, in general? There is no evidence to suggest that ingesting cannabis orally or topically poses a cancer risk.

A Push for Further Research into Marijuana and Cancer

While there is currently no hard evidence that THC/CBD concentrates or whole-plant marijuana cures cancer when used at home, studies continue as researchers work to discover how marijuana might be used as an effective way to battle back cancer. Organizations such as the American Cancer Society are pushing for reclassification of cannabis that will allow more thorough research to explore its medicinal uses.

For now, cannabis has demonstrated its effectiveness at treating a long list of medical conditions, including nausea, pain, and many of the symptoms that people experience as a result of cancer and treatments such as chemotherapy. Even if consuming medical marijuana for cancer doesn’t act as a cure, it’s still a valuable tool for those who are fighting the disease.

Dorothy Harris - CNBS Author: Dorothy Harris
Dorothy is far from being a pot-head. Actually, when we first met she wasn’t very familiar with cannabis - but with her excellent research skills and drive for knowledge, it didn’t take her long to master the field. Dorothy comes from a scientific background and is in charge of researching and writing our advanced scientific and medical topics, as their correctness is not something we are willing to compromise on. Dorothy specializes in top notch research, making sure no stone is left unturned.
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Dave Anderson
Dave Anderson
5 years ago

That is interesting that patients have used cannabis to treat the symptoms of cancer. Maybe it would be good to look into getting cannabis concentrates to help my dad with cancer treatments. This is something I am going to have to look into soon so he doesn’t have to be in so much pain.