Does Smoking Weed Cause Lung Cancer?
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Smoking Weed and Lung Cancer: What the Research Says

Smoking Weed and Lung Cancer: What the Research Says
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Updated on June 20, 2025
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Recreational use of marijuana has gained a lot of momentum since Colorado and Washington became the first states to legalize it in 2012. According to a recent poll by Gallup, roughly 15 percent of Americans say they smoke weed, more than twice the number of Americans who fessed up to doing so 10 years ago.

Lung health experts think smoking anything at all, including weed, is not such a good idea.

 “People should only inhale clean air,” says Janaki Deepak, MD, an expert on lung cancer and COPD at the University of Maryland Medical Center in Baltimore.

So, does smoking weed cause lung cancer? If you’re one of the millions of people who smoke weed either recreationally or for medical purposes, here’s what experts know about the health risks.

What Does Smoking Weed Do to Your Lungs?

Nothing great, experts say. The American Lung Association is concerned about the health impacts of marijuana use and cautions the public to take a pass.

 “One interesting thing we see in the lung disease world with marijuana is that it causes a lot of inhalational lung injury,” says Dr. Deepak. “The small airways of the lungs get highly inflamed, and it produces a lot of damage to the lungs.”

The way the smoke is inhaled is a major factor contributing to that damage. Unlike cigarettes, which are pretty much puffed in the same manner by all users, weed can be smoked in several different ways, including via pipes, bongs, joints, blunts, and vapes. “The different pattern of smoking [marijuana] changes the distribution of the potential chemicals in the lungs,” says Albert Rizzo, MD, chief medical officer for the American Lung Association. And that distribution is likely to cause damage in ways that aren’t yet fully understood.

Weed smokers also tend to inhale more deeply and hold it in longer than tobacco smokers, which leads to a greater exposure to lung-harming tar, says Deepak.

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Does Smoking Marijuana Cause Lung Cancer?

The research at this point does not prove that it does. The landmark National Academies of Sciences report found that there’s no statistical association between cannabis use and the incidence of lung cancer.

 “In terms of lung cancer risk, we will find out much more about that as we go on,” says Deepak.

Establishing the scientific connection between weed and lung cancer has been tricky. “Besides not being studied as thoroughly as tobacco and its relationship to lung cancer, there are other complications that can make it harder to gauge lung-cancer risk,” says Dr. Rizzo, adding that it’s difficult to isolate people who smoke marijuana only, since many users smoke other substances, too. “It can’t really be studied well,” he says.

Other experts concur. “We do not have the same long-term data on marijuana use as we do with tobacco use and the link of tobacco use to cancer, so it is unclear at this point,” says Tyler Nighbor, PhD, principal scientist for tobacco control research at the American Cancer Society. “However, combusted marijuana includes many of the same substances found in tobacco smoke. More long-term data are needed on marijuana use to understand the relationship to lung cancer.”

What Other Health Problems Does Smoking Weed Cause?

Smoking weed can cause chronic bronchitis.

 The smoke can also impair the lungs’ airways, which can cause a chronic cough, phlegm production, and wheezing. But it’s not currently known if these symptoms happen more often in marijuana smokers than in people who don’t smoke weed.

And it’s not just the respiratory system that may take a hit: Smoking weed can also impact the body's ability to fight disease, especially for those whose immune systems are already compromised by drugs or certain health conditions. “THC [the psychoactive compound in cannabis] is a little bit of an immune suppressant,” says Deepak. “THC makes you more likely to get infections, respiratory or otherwise.”

Long-term weed smoking can also lead to other health complications, including:

  • Altered brain development
  • Cognitive impairment
  • Increased risk for psychosis disorders, such as schizophrenia

Is Smoking Weed Worse for You Than Smoking Tobacco?

“The safest thing I can say is that we just don’t know,” says Rizzo. “At the Lung Association, we don’t condone putting anything into your airways that could be causing problems.”

The American Cancer Society agrees. “The combustion of any product can be detrimental to one’s health, regardless of whether it is tobacco or marijuana,” says Dr. Nighbor. “Smoked marijuana delivers harmful substances to users and those closeby, including many of the same substances found in tobacco smoke. Still, we do not have the same long-term data (as we do with tobacco use) on marijuana use.”

Is Vaping Marijuana Any Better for You Than Smoking Marijuana?

Again, more research is needed, but vaping still exposes your lungs to harmful chemicals — if not the tar — and comes with its own set of health risks.

In 2019, a surge of vaping-related emergency department visits across the United States, including at least 60 deaths, was linked to vaping products that contained vitamin E acetate.

 Though case numbers have dropped, there are still people being diagnosed.

 And there’s no real way of knowing if your vape contains that risky ingredient. “Vapes are not regulated by the FDA [U.S. Food and Drug Administration], and they may contain contaminants you’re unaware of,” says Rizzo. “This is an area that’s not regulated, and you can’t trust what you’re using.”

What Should People Do if They Want to Quit Smoking Weed?

While there aren’t as many stop-smoking resources for marijuana as there are for tobacco, there are organizations you can turn to to help you break your weed habit. The Substance Abuse and Mental Health Services Administration has a website with resources and a hotline you can call: 800-662-HELP (4357).

If you use medical marijuana to help manage symptoms of a health condition, edible weed products such as gummies, chocolates, and sodas don’t expose your lungs to harmful smoke. Talk to your doctor about this option if you aren’t in a position to give up using cannabis entirely.

Do know that it can take longer to feel an effect from edible weed products than from smoking weed — as long as four hours in some cases — so start with a low dose (10 milligrams of THC or less) and wait at least 90 minutes before consuming any more to see how your body reacts to it.

The Takeaway

  • Though there may not be a clearly established link to lung cancer, smoking weed causes damage to your lungs.
  • There currently isn’t enough research to compare weed with tobacco smoke, but many of the same substances you inhale can be found in both.
  • If you use medical marijuana for a chronic health condition, edibles won’t expose your lungs to smoke and may be a good alternative.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. What Percentage of Americans Smoke Marijuana? Gallup. November 1, 2024.
  2. Marijuana and Lung Health. American Lung Association. September 9, 2024.
  3. The Health Effects of Cannabis and Cannabinoids. National Academies of Sciences. 2017.
  4. Know the Effects, Risks and Side Effects of Marijuana. Substance Abuse and Mental Health Services Administration. November 7, 2024.
  5. Zulfiqar H et al. Vaping-Associated Pulmonary Injury. StatPearls. June 25, 2023.
  6. E-cigarettes and Vaping. American Cancer Society. November 19, 2024.
  7. Safety with Edibles. Colorado Cannabis.
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David Mannino, MD

Medical Reviewer

David Mannino, MD, is the chief medical officer at the COPD Foundation. He has a long history of research and engagement in respiratory health.

After completing medical training as a pulmonary care specialist, Dr. Mannino joined the Centers for Disease Control and Prevention (CDC) Air Pollution and Respiratory Health Branch. While at CDC, he helped to develop the National Asthma Program and led efforts on the Surveillance Reports that described the U.S. burden of asthma (1998) and COPD (2002).

After his retirement from CDC in 2004, Mannino joined the faculty at the University of Kentucky, where he was involved both clinically in the College of Medicine and as a teacher, researcher, and administrator in the College of Public Health. He served as professor and chair in the department of preventive medicine and environmental health from 2012 to 2017, with a joint appointment in the department of epidemiology.

In 2004, Mannino helped to launch the COPD Foundation, where he served as a board member from 2004 through 2015, chairman of the Medical and Scientific Advisory Committee from 2010 through 2015, and chief scientific officer from 2015 to 2017.

Mannino has over 350 publications and serves as an associate editor or editorial board member for the following journals: American Journal of Respiratory and Critical Care Medicine, Chest, Thorax, European Respiratory Journal, and the Journal of the COPD Foundation. He was also a coauthor of the Surgeon General’s Report on Tobacco in 2008 and 2014.

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Cathy Garrard

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Cathy Garrard is a journalist with more than two decades of experience writing and editing health content. Her work has appeared in print and online for clients such as UnitedHealthcare, SilverSneakers, Bio News, GoodRx, Posit Science, Prevention, Reader's Digest, and dozens of other media outlets and healthcare brands. She also teaches fact-checking and media literacy at the NYU School for Professional Studies.
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