There is plenty of misinformation surrounding the question of whether, and exactly how, cannabis can fight cancer. There’s no doubt that cannabis is the perfect way to counter some of the nastiest side effects of chemo therapy – namely, nausea and vomiting. Studies have also shown that cannabis consumption reduces the amount of pain medication needed by patients in clinical trials. As we all know, cannabis is also great for stimulating appetite. These are all great reasons for cancer patients to use cannabis, and there’s not much room for debate on these points – it may not work for everybody for these purposes, but it certainly works well for many.

But to this day, the American Cancer Society warns that there are no clinical studies yet that show that cannabis can control or cure cancer. They do concede that cannabinoids are safe for treating cancer, but warn that “relying on marijuana alone as treatment while avoiding or delaying conventional medical care for cancer may have serious health consequences.”

This is great advice, but it’s important to also realize how much cannabis research has been limited by the plant’s classification as a Schedule I drug, meaning it has no recognized medical value. Due to federal illegality, cannabis research faces an uphill battle to this day in the US.

With where we are now it’s important to recognize that cannabis is neither the useless drug that the federal government says it is, nor a magic cure – as far as we know.

medical cannabis fighting cancer

On the other end of the spectrum are anecdotal claims that cannabis, and cannabis oil in particular, have “cured” cancer for patients. Dr. Donald Abrams, who is a cannabis advocate and an oncologist at the UCSF Osher Center for Integrative Medicine at Mount Zion in San Francisco, talked to Leafly about the reality of cannabis as a cancer treatment.

“I note that many of the people who are very vocal about how cannabis oil cured their cancers seem to forget that they also received conventional therapies,” said Abrams. He notes that in “33 years of being an oncologist in San Francisco, I would guess that a large proportion of the patients I have treated have used cannabis. If cannabis definitively cured cancer, I would have expected that I would have a lot more survivors.”

However, there is a growing body of pre-clinical evidence (clinical trials mean testing on actual human patients) to suggest that cannabis can slow or even stop the growth of certain types of cancer, detailed in a 2016 article on Herb.com.

In 2012, researchers in Spain found that cannabinoids can prevent metastasis – the process by which cancer cells leave the site of the original tumor and travel to other parts of the body.

Another Spanish team, in 2008, showed that THC can limit the ability of tumors to grow blood vessels, which is what allows tumors to keep growing larger. The researchers examined brain cancer cells specifically, but said that evidence suggests a similar anti-angiogenesis effect in melanoma and skin cancer as well.

The active compounds in cannabis have been shown to have anti-proliferative effects on tumors. This means they inhibit the production of new cancer cells. Since non-stop growth of cancerous cells is one of the biggest problems presented by cancer,  this could be an important factor in treating the disease.

cannabis fighting cancer cells cannabinoids

A 2014 review of studies published in Oncotarget showed that cannabis compounds had an anti-proliferative effect in prostate, lung, and breast cancer. In 2013, Italian researchers showed that CBD can mitigate the “migration, adhesion, and invasion” of cancer cells.

Perhaps most strikingly, CBD and THC have recently both been shown to promote apoptosis in cancer cells. This is the process by which the body destroys its own cells when they have become damaged. The 2016 study, published in Current Oncology, found that these compounds helped to cause this “programmed cell death” in neuroblastoma cells, among the most common types of tumors in children. Normally, tumor cells stop undergoing this process entirely, which is part of the problem that arises from cancer. Cannabinoids may trigger this process, leading cells to die naturally.


The fact is that we are in the earliest stages of substantive research on how cannabis can be useful for cancer patients. The main task now is to legitimize research in the US, and to move toward human clinical trials that can provide more solid evidence of the efficacy of cannabinoids against cancer. This will lead to more definitive answers on what cannabis can and can’t do, and it is one of the many reasons the fight for federal legalization (or at least rescheduling) is so important.

However, there is plenty of evidence that cannabis is safe and useful for helping cancer patients with symptoms, and especially with the side effects of harsh, conventional treatments like chemotherapy. There is also enough evidence to suggest that anti-cancer effects are, at least, a possibility. All of this means that cannabis has a role in the daily routine of cancer patients, even if cannabis as a cancer cure has yet to reach the status of scientific consensus.