Can Marijuana Prevent Cancer?

By Lanny Swerdlow, RN (California)


Dr. Donald Tashkin is a widely published pulmonologist who for three decades has conducted investigations for the National Institute of Drug Abuse and other government agencies on the adverse effects of marijuana and other drugs on the human body.

Studies conducted by Dr. Tashkin in 1990 found that marijuana smoke has almost the exact same carcinogens (cancer causing agents) as tobacco smoke and that the concentration of these carcinogens was exceedingly higher in marijuana smoke. These studies are the basis for the government's warning in thousands of ads that smoking one marijuana joint does as much damage as smoking four cigarettes.

Donald Tashkin

Since it is well documented that the carcinogens in tobacco smoke are directly responsible for the development of lung cancer in tobacco smokers, government marijuana prohibitionists reasoned that marijuana smoke must also cause lung cancer because it contains even stronger concentrations of these cancer causing agents.

To document a connection between lung cancer and marijuana smoking, Dr. Tashkin received a very large grant from the National Institute of Drug Abuse. With over 2,200 subjects, the research was one of the largest case control studies of its kind ever!

The government was horrified at the results and did its best to ignore them as Dr. Tashkin failed to find any link between smoking marijuana and the development of lung cancer. In almost every category studied, a person was no more likely to develop lung cancer if they smoked marijuana than if they didn't smoke marijuana.

How can that be? The marijuana smokers should be developing lung cancer at a significantly higher rate than the non-smokers because they are taking carcinogenic agents into their lungs and the non-smokers are not. What is going on here?

Dr. Tashkin's study offers some evidence of what might be happening. In all the groups studied, the smoker of marijuana was no more likely to develop lung cancer than the non-smoker - save for one group in which there was a small, but still statistically significant difference. This was the group of people who only smoked marijuana and nothing else compared to people who did not smoke anything at all.

In this group of people the smokers of marijuana actually had a lower incidence of lung cancer than the people who did not smoke anything at all.

This makes no sense. How can people who are taking carcinogens directly into their lungs have a lower incidence of lung cancer than people who are not? It makes no sense unless perhaps the cannabinoids found in cannabis are such powerful anti-cancer agents that they can prevent the development of cancers even in the presence of cancer causing agents.

Does Dr. Tashkin's study prove this? No it does not. But there is a lot of scientific evidence out there that appears to show this is exactly what is happening.

In 2003 Dr. Manual Guzman from the University of Madrid authored a medically astounding report detailing current research into the ability of the cannabinoids in cannabis to control the spread of cancer including the results of his studies on cannabinoids injected into the brains of rats with brain tumors. Published in the peer-reviewed research publication Nature Reviews Cancer, he wrote:

Cannabinoids inhibit tumour growth in laboratory animals. They do so by modulating key cell-signalling pathways, thereby inducing direct growth arrest and death of tumour cells, as well as by inhibiting tumour angiogenesis and metastasis. Cannabinoids are selective antitumour compounds, as they can kill tumour cells without affecting their non-transformed counterparts.

The cannabinoids found in cannabis can not only slow the growth of tumors, they can actually selectively kill cancer cells. This is amazing! There are lots of anti-cancer drugs available that are very good at killing cancerous cells. The problem with all of them is that there are also very good at killing all the other cells around them.

Cannabis, on the other hand, can selectively kill only the cancer cells and leave all the unaffected cells alone and does it without the generalized toxic effects of conventional chemotherapies.

Dr. Tashkin's and Dr. Guzman's investigations are part of a virtual cascade of recent research documenting the anti-cancer properties of the cannabinoids found in cannabis.
In November 2007, researchers at the California Pacific Medical Center Research Institute published a report showing that the non-psychoactive cannabinoid cannabidiol found in cannabis can inhibit the spread of breast cancer.

Investigators at the University of Wisconsin School of Medicine and Public Health reported in January 2008 that the administration of cannabinoids halts the spread of a wide range of cancers, including brain cancer, prostate cancer, breast cancer, lung cancer, skin cancer, pancreatic cancer, and lymphoma. Like Dr. Guzman's research, the report noted that cannabis offer significant advantages over standard chemotherapy treatments because the cannabinoids in cannabis are both non-toxic and can uniquely target malignant cells while ignoring healthy ones.

Is the evidence incontrovertible that cannabis can inhibit the spread of cancer, kill cancer cells and prevent the development of cancer? No it is not – but people are spending billions of dollars and ingesting all kinds of supplements on way less evidence then there is to support the anti-cancer properties of cannabis.

When taking any kind of medicine or supplement, a person needs to decide if the claimed benefits of a product outweigh the risks. Many times the answer is no because many medicines and even supplements sold over the counter have significant debilitating and even deadly side effects.

Cannabis, however, is not one of these products as there has never been a single death attributed to cannabis or any other significant debilitating consequences. Further, the vast majority of cannabis users report numerous beneficial effects of taking cannabis including stress reduction, insomnia relief and a general feeling of well being.

If cannabis can prevent the development of cancer, then the appropriate ingestion of cannabis is desirable in the same way that the appropriate ingestion of calcium supplements can prevent or at least delay the onset of osteoporosis. Since for the vast majority of people, cannabis has no negative side effects and only beneficial effects, it would seem that the regular appropriate ingestion of cannabis as a cancer preventative agent would be a prudent course of action.


  1. Tashkin, D.P., Pulmonary Complications of Smoked Substance Abuse. Western Journal of Medicine 1990 May; 152:525-530. pg. 525-526
  2. Guzman M., [2003] Cannabinoids: potential anticancer agents. Nat Rev Cancer. 3(10): 745-55
  3. Mia Hashibe, Hal Morgenstern, Yan Cui, Donald P. Tashkin, Zuo-Feng Zhang, Wendy Cozen, Thomas M. Mack, and Sander Greenland, Marijuana Use and the Risk of Lung and Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control Study
  4. Cancer Epidemiology Biomarkers Prev. 2006 15: 1829-1834.
  5. Sean D. McAllister, Rigel T. Christian, Maxx P. Horowitz, Amaia Garcia and Pierre-Yves Desprez Cannabidiol as a novel inhibitor of Id-1 gene expression in aggressive breast cancer cells, Molecular Cancer Therapeutics, November 1, 2007 6, 2921
  6. Cannabinoids As Chemo Treatment, Journal of Cancer Research, Jan. 31, 2008

© This article is copyrighted by Medical Cannabis Journal 12-01-2013

smoked study  

Write a comment

  • Required fields are marked with *.

If you have trouble reading the code, click on the code itself to generate a new random code.
Showing comments 1 to 10 of 24 | Next | Last
Posts: 24
A really good answer
Reply #24 on : Thu August 07, 2014, 06:45:37
A really good answer, full of raatnoility!
Posts: 24
Ie2€™m uncertain in
Reply #23 on : Thu July 31, 2014, 15:18:27
Ie2€™m uncertain in which you are getintg the info, yet good matter. My partner and i has to invest some time studying more or perhaps comprehending a lot more. Thank you regarding fantastic information My partner and i needed this kind of information regarding my own vision.
Posts: 24
Re: Marijuana: Cancer Prevention?
Reply #22 on : Fri June 20, 2014, 06:07:46
I read a lot about this article! and is ready to admit that it's true! rumor has it that one little-known company (ALPC) from Canada grows marijuana for medical purposes! say where you can buy shares
Posts: 24
Reply #21 on : Wed January 23, 2013, 05:40:57
I don't know who you wrote this for but you hpeled a brother out.
Posts: 24
Re: Marijuana: Cancer Prevention?
Reply #20 on : Tue January 01, 2013, 03:02:40
If people eat marijuana cooked into butter or peanut butter instead of smoking it. It would have an even better anti-cancer effect.
Ojo Oluwatobi
Posts: 24
Reply #19 on : Fri September 14, 2012, 05:25:21
i they smoke and i want u advice me may be to continue nor to dispute, to continue what and what to do to continue, to dispute why and what to do to be disputed
Big Jim
Posts: 24
Weed and cancer
Reply #18 on : Thu June 21, 2012, 23:20:34
I've always had the feeling that cancer doesn't like weed at all. Weed is a blessing from God. It fights off the nightmare of cancer. The right-wing nut balls want us to have to pay them for our cancers. That's why they hate weed. Weed prevents cancer. That costs the greedy medical industry money. That's why they make the best medicine in the world, illegal!
Posts: 24
Re: Marijuana: Cancer Prevention?
Reply #17 on : Tue June 12, 2012, 10:59:39
Fucking lies!!!! How many deaths have been cause from marijuana.
Johm Smith
Posts: 24
Carcinogenic Chemicals
Reply #16 on : Sun May 27, 2012, 02:01:44
Tobacco does not contain carcinogens. The carcinogens in the tobacco smoke come from the chemicals used in the cigarette manufacturing process.
Posts: 24
Don't be brainwashed
Reply #15 on : Sat May 12, 2012, 01:55:40
Don't listen to michelle. First off "Cannabis" is not poison at all. It has no toxic properties whatsoever. Psilocybin mushrooms would also be extremely hard to overdose on. The amount of psilocybin it would take to cause death is an extremely high amount. Alcohol on the other hand is much worse. Alcohol and CNS depressant drugs are the only ones that can cause death from withdrawl effects alone if you have a physical dependance. Not even meth, heroine, or cocaine will do that. I would not however give weed to 13 yr old for asthma even though thc dialates bronchial tubes. The parents should not have gotten in trouble. The weed didn't cause death.
Showing comments 1 to 10 of 24 | Next | Last


A Primer to the Meaning of Proposition 215 and SB420

Read More


Finally in the early 21st century, medicinal cannabis is being rediscovered by physicians and patients alike.

Read More

Why Marijuana is Legal in America

Michael Vandeburg claims in his new book, “Why Marijuana is Legal in America.” The biggest claim in the book is that there are permanent ‘Statutory Federal Rights’ created by congress that makes marijuana legal in America.

Read More

It's A Gray Area: It's time to take back America's moral high ground

President Obama has recently renewed his plans to try to close our military prison at Guantanamo, Cuba, and has also promulgated new guidelines for our government's use of drones to assassinate people in places like Pakistan, Afghanistan and Yemen. Good. It's about time!

Read More


California's Medical Cannabis Guidelines

In August of 2008 California's Attorney General: Jerry Brown released the updated-version of what is referred to as, "The Guidelines for the Security and Non-Diversion of Marijuana Grown for Medical Use". These guidelines were released in August of2008.

Read More


A Primer to the Meaning of Proposition 215 and SB420

Read More


Finally in the early 21st century, medicinal cannabis is being rediscovered by physicians and patients alike.

Read More


Treating Yourself
Michelle R Banner


Blue Planet Nutrients
Honey Bee Extractors
THCF Medical Clinics
420 Science
Phoenix Tears
Medical Cannabis