Medically Reviewed by
Jason Crawford

Article Last Updated on January 3, 2023

The health effects of marijuana have been debated for decades. The main cannabinoids THC (tetrahydrocannabinol) and especially CBD (cannabidiol), have been found to be helpful for various medical conditions (chronic pain, nausea, insomnia, etc.), leading to the approval of cannabis for medical use despite it not being officially approved by the FDA yet.

Following the legalization and decriminalization of recreational and medical marijuana in some states, cannabis use has greatly increased. Cannabis has not only become more available for everyone, but the whole cannabis industry has blossomed. What remained the same as before, though, is smoking as the most common form of consuming marijuana.

Tobacco smoke is known to contain carcinogens and it’s often linked to lung cancer, so there have been questions about whether smoking marijuana causes lung cancer as well. This is what we focus on in today’s article – we’ll take a look at what the implications of smoking cannabis are and what science has to say (so far) about this connection.

What Are the Effects of Marijuana Use on Lung Health?

Overall, smoking marijuana can be aggravating for people who already have respiratory issues as marijuana smoke still contains irritants. Long-term regular use of cannabis can cause symptoms such as persistent coughing, wheezing, and shortness of breath in marijuana smokers.

Some studies state that regular cannabis smoking can cause microscopic injuries to the airways which can lead to chronic bronchitis. Additionally, according to the National Institute on Drug Abuse, marijuana smokers are more likely to experience airway inflammation and develop respiratory issues than nonsmokers. 

However, it was also found that marijuana doesn’t increase the risk of emphysema or COPD (chronic obstructive pulmonary disease), conditions most often associated with smoking cigarettes.

Is Cannabis Smoking Just as Harmful as Cigarette Smoking?

Cigarette smoke is long known to have harmful effects on lung function which can lead to some diseases like chronic bronchitis, emphysema, and COPD (chronic obstructive pulmonary disease). Smoking tobacco is also linked to lung cancer and is considered a major risk factor.

For comparison, tobacco smoke and marijuana smoke both contain many of the same toxic compounds and irritants that get released upon combustion, such as benzopyrene and benzanthracene. However, the main difference between tobacco and marijuana smoking is that marijuana is inhaled deeper and held longer, exposing the lungs to these chemicals. But, due to marijuana’s potency, it’s also less frequently smoked.

On the flip side, tobacco cigarettes are smoked much more frequently, even though the smoke is not held in as long as marijuana smoke. Therefore, it can be said that the exposure to harmful chemicals is prolonged, especially for heavy smokers.

It’s Hard to Make an Accurate Assessment

It’s hard to make an accurate assessment about whether both are equally bad for lung health as studies on the health effects of marijuana smoke have been scarce and inconsistent, as opposed to decades of studies on tobacco smoke that unanimously claim that smoking tobacco cigarettes is harmful.

In the same vein, a study published in the journal Annals of the American Thoracic Society concludes that “the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

What Science Says About Smoking Marijuana and the Increased Risk of Lung Cancer

In short, science says maybe, as the results are mixed. A 2018 review of the literature on the subject provides some insight. 

Marijuana has been illegal for a long time which has prevented large-scale studies to be conducted in order to get conclusive results. Most cellular, animal, and human studies were smaller-scale studies and with inconsistent parameters such as self-reported marijuana use as well as the fact that a lot of the participants were also tobacco smokers which made the job more difficult.

A 2013 study proposed that long-term cannabis smoking may increase the risk of developing lung cancer, while another study has found that the risk of lung cancer increases proportionally to the amount of cannabis smoked. In contrast, a 2014 study has found no connection between lung cancer and smoking marijuana.

What About Secondhand Marijuana Smoke?

Secondhand marijuana smoke is a frequent concern for nonsmokers in regard to drug testing and contact high, as well as potential negative effects. Secondhand tobacco smoke is an obvious irritant, especially for children and individuals with respiratory issues, but what about cannabis?

The effects of secondhand cannabis smoke aren’t fully known, but some animal studies propose that it can be harmful to some vulnerable groups of people and they should stay away for safety reasons.

Is Vaping a Safer Use of Marijuana?

People who avoid smoking often turn to vaping as a healthier alternative to a joint because it doesn’t combust the dry herbs, but it heats them to a certain temperature for the cannabinoids to be extracted. Therefore, the smoke, or vapor, is a lot less harsh. There are also vaporizers that work with pure cannabis extracts or vape cartridges that can contain some additives.

Truth is, vaping hasn’t been scientifically proven to be healthier, especially when it comes to vape cartridges and concentrates, but anecdotal evidence shows that many people enjoy weed through vaping instead of smoking. One plus of vaping weed is that the cannabinoids reach the bloodstream much faster than capsules or edibles, which is especially important for medical uses.

Bottom Line – It’s Difficult to Reach a Definite Conclusion as More Research Is Needed

One reason why there still isn’t a definitive conclusion is that the legal state of cannabis has been a major obstacle for doing deeper research, leaving a lot of questions unanswered. 

While it’s clear that cannabis contains beneficial compounds for medical use, including managing chronic pain and nausea in cancer patients, the research regarding cannabis causing cancer is in need of updating. Plus, there’s the issue of the ingredients of the smoke itself.

Another reason why it has been hard to conduct more comprehensive studies is that many marijuana smokers are also tobacco smokers, so it has been hard to draw the line between the two. Smoke, regardless of where it comes from (including marijuana), does contain harmful chemicals and carcinogens – and this shouldn’t be ignored. 

That said, the relationship between the beneficial compounds of marijuana and the harmful effects of smoke are yet to be investigated in future studies.

Additional Sources

Aldington, S., Harwood, M., Cox, B., Weatherall, M., Beckert, L., Hansell, A., Pritchard, A., Robinson, G., Beasley, R., & Cannabis and Respiratory Disease Research Group (2008). Cannabis use and risk of lung cancer: a case-control study. The European respiratory journal, 31(2), 280–286. https://doi.org/10.1183/09031936.00065707

Holitzki, H., Dowsett, L. E., Spackman, E., Noseworthy, T., & Clement, F. (2017). Health effects of exposure to second- and third-hand marijuana smoke: a systematic review. CMAJ open, 5(4), E814–E822. https://doi.org/10.9778/cmajo.20170112

Novotny M, Merli F, Wiesler D, Fencl M, Saeed T. Fractionation and capillary gas chromatographic—mass spectrometric characterization of the neutral components in marijuana and tobacco smoke condensates. J Chromatogr A. 1982;238:141-50. doi: 10.1016/S0021-9673(00)82720-X

Tashkin DP. Effects of marijuana smoking on the lung. Ann Am Thorac Soc. 2013;10(3):239-247. doi:10.1513/AnnalsATS.201212-127FR

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.