Marijuana and Lung Health The American Lung Association is concerned about the health impacts of marijuana use, especially on lung health. We caution the public against smoking marijuana because of the risks it poses to lung health.
Scientists are researching marijuana, and the American Lung Association encourages continued research into the health effects of marijuana use, especially on lung health.
Marijuana How marijuana affects health is determined by how it's consumed. Marijuana is most commonly smoked, such as from pipes, bongs, paper-wrapped joints, blunts and other items including devices that heat or vaporize marijuana. It can also be consumed through foods and beverages, such as brownies or tea.
While this statement focuses on marijuana and lung health, it's important to note that there are other health concerns outside the lungs attributed to marijuana use that are not addressed here, including neurological and cognitive effects.1,2
Additionally, there are significant public health concerns associated with pediatric poisonings caused by accidental ingestion of edible marijuana products.3
Marijuana Smoke Smoke is harmful to lung health. Whether from burning wood, tobacco or marijuana, toxins and carcinogens are released from the combustion of materials. Smoke from marijuana combustion has been shown to contain many of the same toxins, irritants and carcinogens as tobacco smoke.4-7
Beyond just what's in the smoke alone, marijuana is typically smoked differently than tobacco. Marijuana smokers tend to inhale more deeply and hold their breath longer than cigarette smokers, which leads to a greater exposure per breath to tar.8
Secondhand marijuana smoke contains many of the same toxins and carcinogens found in directly inhaled marijuana smoke, in similar amounts if not more.5 While there is no data on the health consequences of breathing secondhand marijuana smoke, there is concern that it could cause harmful health effects, especially among vulnerable children in the home. Additional research on the health effects of secondhand marijuana smoke is needed.
Lung Health and Marijuana Smoke Smoking marijuana clearly damages the human lung. Research shows that smoking marijuana causes chronic bronchitis and marijuana smoke has been shown to injure the cell linings of the large airways, which could explain why smoking marijuana leads to symptoms such as chronic cough, phlegm production, wheeze and acute bronchitis.4,9
Smoking marijuana has also been linked to cases of air pockets in between both lungs and between the lungs and the chest wall, as well as large air bubbles in the lungs among young to middle-aged adults, mostly heavy smokers of marijuana. However, it's not possible to establish whether these occur more frequently among marijuana smokers than the general population.4
Smoking marijuana can harm more than just the lungs and respiratory system - it can also affect the immune system and the body's ability to fight disease, especially for those whose immune systems are already weakened from immunosuppressive drugs or diseases, such as HIV infection.4,9
Smoking marijuana hurts the lungs' first line of defense against infection by killing cells that help remove dust and germs as well as causing more mucus to be formed. In addition, it also suppresses the immune system. These effects could lead to an increased risk of lower respiratory tract infections among marijuana smokers, although there is no clear evidence of such actual infections being more common among marijuana smokers.4,9 However, frequent marijuana-only smokers have more healthcare visits for respiratory conditions compared to nonsmokers.10
Studies have shown that smoking marijuana may increase the risk of opportunistic infections among those who are HIV positive, although it does not seem to effect the development of AIDS or lower white cell counts.4,9
Another potential threat to those with weakened immune systems is Aspergillus, a mold that can
