Marijuana Smoke Crippled the Lung Cells That Kill Bacteria in Rats ↗
Marijuana smoke reduced lung immune cell bacteria-killing from 78% to 11% in a dose-dependent pattern. The toxic component was in the gas phase, not THC.
Respiratory research
Explore published research on respiratory, including study methods and limitations.
A 1978 Medical Review Found Cannabis Had Both Therapeutic Promise and Health Risks ↗
A 1978 medical review identified cannabis as promising for glaucoma and asthma but flagged cardiovascular risks during exercise and preliminary concerns about lung and immune effects.
A Major 1986 Review Found Cannabis's Greatest Health Concern Was Its Effect on Young Users ↗
A major 1986 pharmacological review found cannabis's greatest health concern was its impact on youth development, while finding no proven brain damage and limited physical dependence in adults.
A Cancer Patient Developed a Dangerous Lung Fungal Infection Possibly Linked to Contaminated Marijuana ↗
A cancer patient developed a dangerous lung fungal infection while using illicitly obtained marijuana during chemotherapy, highlighting contamination risks for immunocompromised users.
Daily Marijuana Smoking Damaged Airways Like Tobacco, but Lung Disease Would Take 30+ Years of Heavy Use ↗
Daily marijuana smoking produced tobacco-like respiratory symptoms, but COPD would likely require 4-5 joints daily for 30+ years. Cancer risk was documented in case reports but not quantified.
What Science Actually Knew About Medical Cannabis in 2001 ↗
Comprehensive review finding solid evidence for cannabinoids in nausea and appetite, emerging evidence for pain and spasticity, and weak evidence for glaucoma and asthma, while advocating for non-smoked delivery methods.
Marijuana Smoke Weakened Lung Immune Cells' Ability to Kill Bacteria ↗
Study finding marijuana smoke impaired lung macrophage bacterial killing through nitric oxide suppression, unlike tobacco smoke, though the impairment was reversible with immune stimulation.
Marijuana Smoking Causes Airway Inflammation and Cell Changes But Evidence for COPD and Lung Cancer Remains Limited ↗
Review found marijuana smoking causes airway inflammation, chronic cough, and precancerous cell changes, but epidemiological evidence for COPD and lung cancer remained limited and inconsistent.
Pooled Analysis From North Africa Found Cannabis Smoking Linked to 2.4-Fold Higher Lung Cancer Risk ↗
Pooled analysis of 430 lung cancer cases from North Africa found cannabis smoking associated with 2.4x higher risk after adjusting for tobacco, with combined tobacco+cannabis use carrying an 18.2x risk.
Marijuana Smoke Contains Some Chemicals at Higher Levels Than Tobacco Smoke ↗
Systematic comparison found marijuana smoke contained up to 20x more ammonia and 3-5x more HCN than tobacco, but lower levels of some carcinogenic PAHs in mainstream smoke.
Cannabis Smoking Was Linked to Higher Risk of Nasopharyngeal Cancer in North Africa ↗
In a study of 636 NPC patients and 615 controls across North Africa, marijuana smoking independently elevated nasopharyngeal cancer risk, separate from cigarette smoking effects.
Cannabis smoking may contribute to lung disease, pneumothorax, infections, and possibly lung cancer ↗
Review found emerging evidence linking habitual cannabis smoking to COPD, pneumothorax, respiratory infections, and potentially lung cancer.
Comprehensive review found recreational cannabis harms were generally minor but could be serious in vulnerable individuals ↗
Comprehensive review found recreational cannabis adverse effects were generally minor, with overall harms appearing less serious than alcohol, though vulnerable individuals faced greater risks.
Cannabis smoking causes airway inflammation and bronchitis but surprisingly limited evidence for COPD or emphysema ↗
Cannabis smoking consistently caused airway inflammation and bronchitis but surprisingly little evidence supported COPD or emphysema risk, and lung cancer evidence was inconclusive.
Pilot test of whether cannabis extract helps breathlessness in COPD patients ↗
Tiny pilot found cannabis extract may change how COPD patients perceive breathlessness without affecting standard measurements.
CBD Reduced Lung Inflammation in Mice Through Adenosine Receptor Activation ↗
A single dose of CBD reduced lung inflammation across multiple markers in mice, working through the adenosine A2A receptor pathway.
Marijuana smoke is not harmless to lungs, but cancer link remains unproven ↗
Review found regular marijuana smoking causes bronchitis symptoms and airway inflammation, while occasional use does not increase COPD risk and the cancer link remains unproven.
Marijuana Smoke Affects the Lungs Similarly to Tobacco but May Not Cause COPD ↗
Review found marijuana smoke causes cough and sputum similar to tobacco but does not appear to cause COPD, with mixed and unclear evidence on cancer risk.
Butane hash oil production burns surged in Colorado after marijuana liberalization ↗
29 burn patients admitted to a Colorado burn center from homemade butane hash oil extraction, with cases increasing sharply after marijuana liberalization.
How Marijuana Smoke Affects Lung Function in U.S. Adults ↗
Large U.S. survey found up to 20 joint-years of marijuana use did not impair lung function. Heavier use altered airflow patterns, but differently from tobacco-related lung disease.
Adding Cannabis to Tobacco Smoking Worsens Lung Health ↗
Scottish study of 500 smokers found adding cannabis to tobacco was associated with worse respiratory symptoms and a small increase in COPD rates beyond tobacco alone.
Young Adults Allow Marijuana Smoke in Their Homes More Than Cigarette Smoke ↗
Survey of 2,002 college students found 17% allowed marijuana smoking in their homes versus 14.5% for cigarettes, with different social factors predicting each.
Is Vaping Cannabis Actually Better for Your Lungs Than Smoking It? ↗
Vaping cannabis reduces toxic smoke exposure, but the lung health advantage over smoking may be smaller than the benefit e-cigarettes offer over tobacco.
Systematic Review Links Smoked Marijuana to Lung Cancer Risk, Emphysema, COPD, and Multiple Respiratory Symptoms ↗
Systematic review of 48 studies found smoked marijuana is associated with lung cancer risk, emphysema, COPD, and respiratory symptoms including wheezing, cough, and phlegm.
Cannabis Smoking May Not Damage Lungs the Same Way Tobacco Does ↗
Literature review finds cannabis smoking causes bronchitis symptoms but, unlike tobacco, is associated with increased lung capacity, possibly due to cannabis's bronchodilator and anti-inflammatory effects.
Just One Minute of Marijuana Secondhand Smoke Impaired Blood Vessel Function for 90 Minutes ↗
Just one minute of marijuana secondhand smoke impaired blood vessel function for 90+ minutes, longer than tobacco smoke, and the effect was caused by combustion products, not cannabinoids.
Marijuana Smokers Had Higher Levels of Toxic Combustion Chemicals in Their Urine ↗
National survey data shows exclusive marijuana smokers had significantly elevated urinary levels of carcinogenic combustion by-products (PAHs, VOC metabolites) compared to non-users.
Cannabis Smoke Affects Lungs Similarly to Tobacco With Some Additional Risks ↗
Review finds cannabis smoke causes bronchitis, may lead to pneumonia and airway obstruction, and poses a potential but inconclusive lung cancer risk with long-term heavy use.
Cannabis use disorder diagnoses nearly tripled in US hospitals from 2002 to 2011, with patients getting older and sicker ↗
Cannabis use disorder diagnoses in US hospitals nearly tripled from 2002-2011, with psychiatric disorders as the top comorbidity and patients trending older and sicker.
Marijuana smoke contains many of the same harmful compounds as tobacco smoke and affects the lungs ↗
Pulmonology review showing marijuana smoke shares many harmful combustion products with tobacco smoke, affecting the respiratory tract of the estimated 2.5-5% of people who use cannabis globally.
Marijuana Smoke Caused More Severe Lung Damage Than Tobacco Smoke in Mice ↗
First systematic comparison showing marijuana smoke caused earlier and more severe lung damage than tobacco in mice over 4 months, with effects independent of CB1 cannabinoid receptors.
What Happens When You Breathe in Someone Else's Marijuana Smoke ↗
Systematic review of 15 studies finding secondhand marijuana smoke causes detectable cannabinoid metabolites, psychoactive effects, and eye irritation, with THC content and ventilation as key factors.
Does Cannabis Improve Athletic or Exercise Performance? The Evidence Says No ↗
Systematic review of 15 studies finding THC does not improve aerobic performance or strength, inhibits exercise-induced asthma, and triggered angina at lower workloads in all cardiac-vulnerable subjects.
E-Cigarette Use Was Linked to Asthma in Adolescents, Independent of Marijuana and Cigarette Smoking ↗
Survey of 6,089 Hawaiian teens found e-cigarette use independently associated with asthma (aOR 1.48), while marijuana and cigarette use were not significant after controlling for e-cigarettes.
Regular Marijuana Smoking Was Linked to Worse Self-Rated Health, Especially When Combined with Tobacco ↗
National survey found regular marijuana smoking associated with 34% higher odds of poor self-rated health even without tobacco, rising to nearly double with concurrent tobacco use.
16% of Hospitalized Toddlers in Colorado Had Detectable Marijuana Metabolites in Their Urine ↗
Study of 43 hospitalized Colorado toddlers found 16% had detectable marijuana metabolites, with higher rates in non-white children and those exposed to tobacco smoke.
Vaporized cannabis did not help breathing or exercise endurance in people with severe COPD ↗
Randomized trial of 16 adults with severe COPD found vaporized cannabis had no meaningful effect on breathlessness, exercise capacity, or lung function.
Teenagers who smoke blunts often pick up cigarillo smoking as a separate tobacco habit ↗
Interviews with 30 teens found marijuana blunt use frequently led to standalone cigarillo tobacco smoking, with group sharing and substitution driving co-use.
A review found cannabis has not been proven to cause lung cancer but evidence remains limited ↗
Review found smoking cannabis has not been proven to cause lung cancer, while noting emerging therapeutic potential for chemo-related nausea and cancer pain. Better studies needed.
Cannabis smoke triggers many of the same harmful changes in airway cells as tobacco smoke ↗
Lab study found cannabis smoke triggered DNA damage, impaired immune defenses, and caused inflammatory responses in human airway cells strikingly similar to tobacco smoke.
A young man developed delayed brain hemorrhage days after synthetic cannabis use ↗
A 25-year-old developed delayed brain hemorrhage days after synthetic cannabinoid use, despite an initially normal brain CT, highlighting the risk of late intracranial complications.
Standard drug tests miss a lot of teen marijuana use, and tobacco smoking strongly predicts it ↗
High-sensitivity testing found 25% of urban teens positive for THC, far more than standard tests detected. Cigarette smokers had 13x the odds of marijuana use.
Cannabis smoke can trigger asthma attacks and allergic reactions, and these risks are often overlooked ↗
A review found cannabis smoke can trigger asthma attacks and allergic reactions, with users showing more symptoms and medical visits, making cannabis an underrecognized respiratory disease trigger.
Cannabis secondhand smoke exposure in apartments is as common as tobacco secondhand smoke ↗
A survey found 7.5% of Ontario apartment residents were involuntarily exposed to cannabis smoke from neighbors, similar to tobacco smoke exposure (6.6%), with lower-income residents most affected.
Utah EVALI investigation: 92% of hospitalized patients had used THC vaping products ↗
Utah EVALI investigation found 92% of patients used THC vaping products, with vitamin E acetate detected in 89% of tested THC cartridges.
Review draws parallels between cardiovascular harms of cannabis and tobacco smoking ↗
Review finds cannabis smoking produces similar combustion chemicals and cardiovascular risks as tobacco, including heart attacks, arrhythmias, and strokes, potentially at younger ages.
Systematic review links cannabis smoking to voice changes, respiratory symptoms, and darkened vocal folds ↗
Systematic review links cannabis smoking to darkened vocal folds, respiratory symptoms, and lung function changes in heavy users, with vaporizing offering symptom reduction.
The 2019 vaping lung injury outbreak: 805 cases, 12 deaths, most linked to THC products ↗
The 2019 EVALI outbreak caused 805 lung injury cases and 12 deaths. Over three-quarters of patients with substance data reported using THC vaping products.
Indoor cannabis smoke was linked to worse child health outcomes in homes with smokers ↗
Indoor cannabis smoking was associated with higher air particle levels and a non-significant trend toward worse child health outcomes in homes where tobacco was already smoked.
THC from vaping deposits on room surfaces, creating potential third-hand exposure ↗
THC was detected on room surfaces after cannabis vaping at levels up to 4,882 ng/m2, demonstrating third-hand cannabis exposure potential.
Heavy marijuana smoking linked to COPD and faster lung decline in older adults ↗
Study of 1,285 adults aged 40+ found heavy marijuana smoking more than doubled COPD risk and accelerated lung decline beyond tobacco alone.
What inhaled cannabis smoke does to the lungs ↗
Review finds cannabis smokers show similar airway symptoms as tobacco smokers, plus unique immune cell deficits, but COPD progression from cannabis alone remains unclear.
Regular cannabis use linked to asthma, COPD, and pneumonia even without tobacco ↗
Analysis of nearly 9,000 cannabis users found elevated risk of asthma, COPD, and pneumonia even among those without tobacco use disorder.
Severe lung injury in adolescent from vaping cannabis oil ↗
Case report of an adolescent with severe lung injury from vaping cannabis oil, highlighting emerging respiratory risks.
Cannabis vaping can cause acute respiratory failure requiring ventilation ↗
Review of cannabis vaping lung injury cases found acute respiratory failure as a serious complication, identifying key cannabis oil ingredients as potential causes.
Two-thirds of NYC public housing residents reported secondhand marijuana smoke exposure ↗
Survey of 1,030 NYC subsidized housing residents found 67% experienced secondhand marijuana smoke in their homes, exceeding cigarette smoke exposure.
Landmark study identified vitamin E acetate as the primary toxicant behind the 2019 vaping lung injury outbreak ↗
A CDC/NEJM study found vitamin E acetate in 94% of EVALI patients' lung fluid across 16 states, with 94% of patients linked to THC vaping, identifying the primary toxicant behind the 2019 vaping lung injury outbreak.
Systematic review documents acute eosinophilic pneumonia from marijuana, vaping, and waterpipe use ↗
A systematic review found 12 cases of acute eosinophilic pneumonia from marijuana, vaping, and other non-cigarette products. Most patients were young, many needed ICU care, but all recovered with corticosteroid treatment.
Case report of acute respiratory failure from lipoid pneumonia after THC vape cartridge use ↗
A previously healthy 28-year-old developed acute respiratory failure from lipoid pneumonia 2 weeks after using a street-bought THC vape cartridge, confirmed by BAL staining and treated with IV corticosteroids.
Review of EVALI vaping lung injury links cases primarily to THC-containing products and vitamin E acetate ↗
Review of the 2019 EVALI outbreak links cases primarily to vaping unlicensed THC products containing vitamin E acetate, with about 2% mortality and predominant presentation in young men.
Cannabis and vaping may affect sedation and pain management during surgery ↗
Review found cannabis users may need more sedation and pain medication during surgery, with THC vaping adding respiratory risks from potential lung injury.
CBD reversed ARDS symptoms in mice by upregulating apelin, a peptide involved in immune regulation ↗
Mouse study found CBD reversed ARDS symptoms and increased apelin expression in lungs and blood, revealing a new CBD mechanism for respiratory inflammation.
One in four US adults reported recent marijuana secondhand smoke exposure, but 81% opposed public marijuana smoking ↗
Survey of 4,088 adults found 27.4% had recent marijuana secondhand smoke exposure in public, while 81% opposed public marijuana smoking and 52.4% perceived it as harmful.
Cannabis vaping doubled among U.S. adults from 2017 to 2019, with the biggest jump in young adults ↗
Cannabis vaping doubled among U.S. adults from 2017 to 2019, tripling among 18-24 year olds. While not linked to respiratory symptoms, cannabis vaping was strongly associated with heavy drinking and other high-risk behaviors.
New mouse model shows cannabis smoke triggers specific immune changes in the lungs ↗
Validated mouse model showed cannabis smoke increased lung macrophages without neutrophil infiltration, plus elevated immune mediators, in both male and female mice.
Cannabis smoking causes bronchitis but a surprisingly different lung pattern than tobacco ↗
Review found cannabis smoking causes bronchitis and increases airway resistance but does not clearly cause COPD, emphysema, or lung cancer, a pattern distinctly different from tobacco.
COPD patients who used cannabis had lower odds of dying in hospital and getting pneumonia ↗
Analysis of 6 million COPD hospitalizations found cannabis users had 37.6% lower odds of in-hospital death and 11.8% lower odds of pneumonia compared to non-users.
E-cigarette and other substance use predicted which teens started vaping marijuana ↗
A national longitudinal study of 7,821 US adolescents found that existing substance use, particularly other marijuana products and e-cigarettes, strongly predicted starting to vape marijuana.
Cannabis smoking linked to oral bacteria that caused brain changes in mice ↗
A study found chronic cannabis smokers had elevated oral Actinomyces meyeri bacteria. When this bacterium was fed to mice for six months, it decreased activity and increased amyloid-beta production in their brains.
Mixed Tobacco and Marijuana Smoking Linked to Rare Lung Condition ↗
A 48-year-old man with long-term tobacco and cannabis smoking developed vanishing lung syndrome, a rare form of severe emphysema, highlighting potential additive respiratory risks from dual use.
One-Third of NYC Families in Apartments Report Marijuana Smoke Drifting In ↗
Survey of 382 NYC families found 31% reported marijuana smoke entering their homes while with their children, with public housing residents 3.45 times more likely to be exposed.
One in Five Toddlers Tested Positive for Marijuana Metabolites ↗
Study of 53 young children in NYC found 20.8% had detectable marijuana metabolites in their urine, with rates nearly tripling in housing where smoking was allowed.
Global survey of 107,000 people finds cannabis smoked at home more often than tobacco ↗
A global survey of 107,272 people found cannabis was more commonly smoked indoors than tobacco, with 78.8% of cannabis-only users smoking at home vs. 67.9% of tobacco-only users.
Commentary finds cannabis vaporizers reduce carbon monoxide and respiratory symptoms but are not risk-free for new users ↗
Cannabis vaporizers reduce respiratory toxins and symptoms compared to smoking but are not risk-free, especially for new users who face cognitive impairment and dependence risks.
Millions report secondhand cannabis smoke exposure at home in the U.S. and Canada ↗
Large survey found about 1 in 5 residents reported secondhand cannabis smoke at home, with higher rates in multi-unit housing across both legal and illegal jurisdictions.
First reported case of air leaking into the spine from cannabis hyperemesis vomiting ↗
First case of pneumorrhachis (spinal air leak) linked to cannabinoid hyperemesis syndrome, caused by severe, repeated vomiting.
Pulmonary circulation disorders in cannabis users tripled over seven years with doubled mortality risk ↗
Among 3.3 million cannabis hospitalizations, pulmonary circulation disorders increased 200% over 7 years, with patients facing 2x the in-hospital mortality risk.
Children exposed to secondhand marijuana smoke had more respiratory infections ↗
Children of caregivers who smoked marijuana had 26% more viral respiratory infections per year compared to unexposed children in a survey of 1,500 families.
Marijuana causes bronchitis but probably does not cause COPD or lung cancer ↗
Marijuana causes bronchitis but the evidence suggests it does not cause COPD and probably does not cause lung cancer, a distinctly different pattern from tobacco.
Marijuana use was not associated with bladder cancer recurrence in a large prospective study ↗
Among 1,472 bladder cancer patients, marijuana use (25%) was not linked to recurrence, while tobacco smoking duration strongly predicted cancer return.
Profile of Adults Who Use Both Marijuana and E-Cigarettes in Utah ↗
Population survey found adults using both marijuana and e-cigarettes were 12 times more likely to be under 30 and had elevated rates of poor mental health, respiratory conditions, and cigarette smoking.
Secondhand Cannabis Bong Smoke Produced Significant Fine Particulate Matter in a Home Setting ↗
Study measured fine particulate matter from secondhand cannabis bong smoke in a home, showing bystanders face meaningful PM2.5 exposure during social smoking sessions.
One Marijuana Joint Produced 4.4 Times More Fine Particles Than a Tobacco Cigarette Indoors ↗
Controlled experiments found one marijuana joint produced 4.4 times more fine particulate matter than a tobacco cigarette in a home, with smoke detectable in all 9 rooms.
Comprehensive review found smoking marijuana causes bronchitis but likely not lung cancer ↗
Review found smoking marijuana causes chronic bronchitis symptoms but no significant FEV1 decline, and most studies have not linked it to lung cancer.
Cannabis use was not linked to respiratory ER visits but was associated with more overall hospitalizations ↗
Ontario population study of 35,000+ people found cannabis use was not linked to respiratory ER visits but was associated with 22% more all-cause hospitalizations.
Families in Public Housing Faced Much Higher Marijuana Smoke Exposure During the Pandemic ↗
NYC survey found 30.7% of families experienced marijuana smoke incursions during the pandemic, with families in subsidized housing facing nearly 7 times the odds and their children having 3 times the asthma rate.
Synthetic Cannabis K2/Spice Caused Life-Threatening Lung Bleeding in a 34-Year-Old Man ↗
A 34-year-old man developed life-threatening lung bleeding (diffuse alveolar hemorrhage) after smoking K2/Spice synthetic cannabis, successfully treated with IV steroids.
More Americans now believe cannabis smoking is safer than tobacco, but science doesn't fully support that view ↗
JAMA study found 44% of US adults now view daily cannabis smoking as safer than tobacco, up from 37% in 2017, a perception that diverges from existing evidence on smoke risks.
Secondhand marijuana smoke reached concerning levels at golf courses and other outdoor locations ↗
Pilot study found secondhand marijuana smoke PM2.5 levels up to 149 ug/m3 at golf courses and public parks, with over 20% of golf course visits encountering exposure.
Prenatal Cannabis Exposure Disrupted Breathing Regulation in Offspring With Sex-Specific Effects Lasting Into Adolescence ↗
Prenatal cannabinoid exposure disrupted breathing regulation in rat offspring sex-specifically: males had altered CO2/O2 responses while females had increased apnea with reduced brainstem serotonin neurons.
Review Examines How Inhaled Cannabis Affects Lung Immune Defenses, With More Questions Than Answers ↗
Review found inhaled cannabis dampens lung immune function, potentially reducing inflammation but also impairing pathogen defense, with major knowledge gaps remaining.
CBD Oil and Vitamin E Acetate in Vaping Products Adhered to and Damaged Human Airway Cells in Lab Tests ↗
Lab study showed CBD oil and vitamin E acetate in vaping aerosols accumulated on and inside human airway cells, causing dramatic cell death and metabolic stress.
A Scoping Review Found Very Little Research on Cannabis Use Among ICU Patients ↗
Scoping review of 2,589 articles found only 22 studying cannabis in ICU settings, revealing major research gaps and inconsistent findings on outcomes.
Among 167,000 ICU Pneumonia Patients, Cannabis Misuse Was Not Independently Linked to Higher Mortality ↗
Among 167,095 ICU pneumonia patients, alcohol misuse increased mortality while cannabis misuse showed no independent association after statistical adjustment.
Systematic review confirms marijuana smoking harms the respiratory system ↗
Systematic review finds marijuana smoking linked to airway inflammation, chronic bronchitis, and possible associations with pneumonia and emphysema.
E-cigarettes, combustible cigarettes, and cannabis each independently linked to asthma in California teens ↗
Population study of 150,634 California teens found e-cigarettes, cigarettes, and cannabis each independently associated with asthma, with additive combined effects.
Heavy cannabis use led to bullous lung disease and a collapsed lung in a young man ↗
Case report documents spontaneous pneumothorax from cannabis-induced bullous lung disease in a young adult, highlighting an underrecognized smoking complication.
Smoking Marijuana and Your Lungs: Chronic Bronchitis Symptoms but No Clear Long-Term Damage ↗
Smoked marijuana causes bronchitis symptoms and airway changes, but hasn't been linked to progressive lung function decline or clearly increased lung cancer risk — a paradox given its similarity to tobacco smoke.
Cannabis hospitalization and tuberculosis rates overlapped geographically in Thailand but causal link unconfirmed ↗
Thai national analysis found geographic overlap between cannabis and TB hospitalizations, with a non-significant 48% higher TB hazard in those with prior cannabis admission, leaving the causal question open.
Sharing cannabis bongs linked to 4x higher tuberculosis risk in Thailand ↗
Thai case-control study found sharing cannabis bongs associated with 4.2x higher TB odds, with a population-attributable fraction (12.2%) nearly equal to tobacco smoking (12.6%), suggesting device sharing is the key risk behavior.
Nearly half of Oklahoma adults reported secondhand cannabis smoke exposure, linked to respiratory symptoms ↗
Survey of 5,410 Oklahoma adults found 42% had recent secondhand cannabis smoke exposure, with higher respiratory symptoms especially among those who also used cannabis, and disproportionate exposure among young, minority, and lower-SES populations.
How You Use Cannabis Changes What It Does to Your Heart and Lungs: A Systematic Review by Route ↗
Systematic review finds smoking cannabis carries the most cardiovascular and respiratory risks, vaping may reduce respiratory harm, and edibles/dabbing are poorly studied.
California Teens Exposed to Marijuana Secondhand Smoke at Rates Similar to Tobacco ↗
California survey of ~159,000 students found secondhand marijuana smoke exposure nearly as common as tobacco secondhand smoke, with higher rates among students with asthma.
Vaping Cannabis, Nicotine, or Both: All Three Linked to Respiratory Symptoms in Young Adults ↗
National survey of 8,033 young adults found cannabis vaping associated with wheezing and cough at rates comparable to nicotine vaping — dual vaping had the worst respiratory symptoms.
People Who Think Secondhand Cannabis Smoke Is Harmful Are Less Likely to Smoke at Home ↗
21-country survey of 28,154 drug users found higher perceived harm from secondhand cannabis smoke was associated with 70% greater odds of not smoking cannabis at home.
Believing Secondhand Cannabis Smoke Is Harmful Was Strongly Linked to Home Smoking Bans ↗
US survey of 21,381 adults found perceiving secondhand cannabis smoke as "extremely harmful" was associated with 6x higher odds of banning cannabis smoking in the home.
Most Cannabis Users Worldwide Smoke at Home, Exposing Others to Secondhand Smoke ↗
Global Drug Survey of 64,000 cannabis users found about 64% smoked at home, with daily home smoking in roughly 25-28%, raising concerns about residential secondhand smoke exposure.
Cannabis Vaping and Smoking Trigger the Same Inflammatory and Cancer Gene Pathways in Lung Cells ↗
Despite fewer toxicants in vapor, cannabis vaping triggered the same inflammatory, cancer, and stress gene pathways in lung cells as smoking — questioning the harm reduction narrative at the molecular level.
43% of Cystic Fibrosis Patients Surveyed Use Cannabis, Mostly for Medical Reasons ↗
Survey of 110 Canadian CF patients: 43% use cannabis, 85% for medical reasons (stress, insomnia, anxiety). Most rate it effective. Legalization reduced stigma.
Cannabis Users See Similar Health Risks for Vaping and Smoking, With Some Exceptions ↗
Survey of 302 cannabis users found few perceived differences between vaping and smoking risks, though younger users and women saw more mental health benefits from vaping.
Legal Cannabis Vape Products Contained Metal Particles from the Vaping Device Itself ↗
Legal Canadian cannabis vape products contained metal particles from device components in both liquid and inhaled aerosol.
Cannabis smoking harms the lungs but its link to lung cancer remains surprisingly unclear ↗
Cannabis smoking clearly causes bronchitis symptoms and impairs lung immune function, but decades of research have failed to establish a consistent link to lung cancer despite the presence of known carcinogens in the smoke.
Hemp Cigarettes Contain Similar Metal Levels as Tobacco, with Lower Cadmium but Higher Chromium in Some Brands ↗
Lab analysis of 14 hemp cigarette brands found metal levels similar to tobacco, with lower cadmium but several brands exceeding state limits for other metals.
States with Legal Cannabis Saw More Asthma Hospitalizations ↗
Difference-in-differences analysis found states with cannabis dispensaries and legal recreational cannabis had 14-20% more asthma hospitalizations than comparison states.
Vaped THC Promotes Candida Growth, Biofilm Formation, and Virulence Gene Expression ↗
Vaped THC promoted Candida albicans growth, biofilm formation, and virulence gene expression in a dose-dependent manner in vitro.
Cannabinoid Vaping Products Contain High Concentrations and Potentially Toxic Byproducts ↗
A review found unregulated cannabinoid vaping products contain high concentrations and produce potentially toxic heating byproducts called quinones that may damage lung tissue.
Cannabis Users Had 31% Higher Odds of Having Asthma in a Meta-Analysis ↗
Meta-analysis of 8 studies found cannabis users had 31% higher odds of asthma diagnosis than non-users, with consistent results across sensitivity analyses.
Blocking Cannabis Receptor Reduced Weight and Improved Asthma in Obese Mice ↗
CB1 receptor blocker caused 27% weight loss in obese mice and improved airway function, identifying the endocannabinoid system as a link between obesity and asthma.
Cannabis Concentrate Vaping Produces Substantial Toxic Byproducts ↗
Review finds cannabis concentrate vaping produces significant toxic byproducts and some products contain hazardous additives, as research lags far behind market growth.
People Hospitalized for Cannabis Use Disorder Had Nearly 3x the Death Risk Over 5 Years ↗
An Ontario study of 11.6 million people found that individuals hospitalized for cannabis use disorder were nearly 3 times more likely to die within 5 years, with especially high risks for suicide and trauma.
Cannabis Industry Workers Are Developing Work-Related Asthma ↗
Multi-state surveillance identified 30 cases of work-related asthma in cannabis workers, mostly from dust exposure in indoor cultivation, including two fatalities.
Adolescent Cannabinoid Exposure Primed Mouse Lungs for Worse Infections Later ↗
Mouse study found adolescent cannabinoid exposure primed lungs for worse bacterial infections in adulthood, amplified when combined with alcohol.
Prenatal Cannabinoid Exposure Impaired Breathing and Heart Reflexes in Young Rats ↗
Animal study found prenatal cannabinoid exposure impaired breathing reflexes and cardiovascular responses in juvenile rats, with sex-specific effects.
Cannabis Plus Tobacco Smokers Had More Aggressive Lung Cancers Than Tobacco-Only Smokers ↗
Prospective study of 150 young lung cancer patients found 39% smoked both cannabis and tobacco, with dual smokers showing more aggressive cancers and emphysema than tobacco-only smokers.
Daily Inhaled Cannabis Linked to Higher Odds of Asthma and COPD in Nearly 380,000 Adults ↗
Analysis of 379,049 adults found daily inhaled cannabis associated with 44% higher asthma odds and 27% higher COPD odds, persisting after tobacco adjustment.
Prenatal THC Exposure Reduced Lung Capacity in Infant Monkeys ↗
Primate study found prenatal edible THC exposure reduced infant lung volumes and altered lung gene expression through epigenetic changes at 6 months of age.
Cannabis Use Disorder Linked to 2.4x Higher Mortality in Hospitalized Asthma Patients ↗
National analysis of 552,160 asthma hospitalizations found cannabis use disorder associated with 2.4x higher mortality, 35% more severe exacerbations, and higher hospital charges.
Children Exposed to Secondhand Cannabis Smoke Have Higher Rates of Respiratory Symptoms ↗
A survey of 3,200 parents found children exposed to secondhand cannabis smoke had 2.1x higher wheezing risk and 1.8x higher nighttime cough risk.
Cannabis Smoke Combined With Seed Oil Diet Weakened Heart Function and Blocked Inflammation Resolution in Mice ↗
Cannabis smoke plus seed oil diet weakened heart function, suppressed anti-inflammatory mediators, and increased immune activation in mice.
Vaping Cannabis Triggers Cancer, Inflammation, and Oxidative Stress Genes in Lung Cells ↗
Cannabis vapor activated cancer, inflammation, and oxidative stress genes in human lung cells—without triggering DNA damage, suggesting a unique harm mechanism.
Smoking vs. Vaping Cannabis: Different Risks, Not No Risks ↗
Vaping cannabis reduces some combustion harms but produces similar cardiovascular effects to smoking and introduces its own lung risks—not a safe alternative.
Smoking Cannabis with Tobacco Changes Lung Disease Patterns in COPD Patients ↗
First study of COPD patients finds combined cannabis+tobacco smoking produces higher lung volumes and 4x more bullous emphysema than tobacco alone, suggesting distinct cannabis lung damage.
The Most Detailed Look Yet at What Cannabis Smoking Does to the Lungs ↗
Multi-modal Canadian study found heavy cannabis smokers had worse lung function, airway structural changes, and overproduction of mucus-related genes in airway cells.
Combining methamphetamine and cannabis was linked to more severe asthma attacks requiring intubation ↗
Co-use of methamphetamine and cannabis linked to higher intubation rates and more severe asthma attacks among hospitalized patients.
Nearly half of current cigarette smokers in high-tobacco states also use cannabis, averaging 19 days per month ↗
Survey of 9,100 adults found 45% of cigarette smokers in high-tobacco states also use cannabis, with co-use most common among young, male, and disabled individuals.
The 20-Year Study That Found Moderate Pot Smoking Doesn't Hurt Your Lungs ↗
CARDIA cohort, 5,115 people, 20 years: cannabis smoking showed a nonlinear pattern — slight lung function improvement at low exposure, leveling off at moderate, trend toward decline only at very high exposure. The opposite of tobacco's linear harm.