Rehab 4 Addiction

Cannabis refers to a substance derived from the three species of the cannabis plant: cannabis sativa, cannabis indica and cannabis ruderalis.

It is often used on a recreational basis as it can produce a feeling of relaxation and pleasure.

The most common way to use cannabis is to smoke the dried leaves and flowers, either through a joint or a bong. This practice releases smoke which is then inhaled into the lungs, held for a few moments and then exhaled. [1]

Some people choose to vape cannabis, which involves inhaling it through a device that heats a liquid form of this substance.

It is then released as vapour which is inhaled and released in a similar fashion as described above.

Cannabis may be combined with food, such as brownies or other baked goods, and then consumed in edible form.

It can also be concentrated into an oil or another form of extract, which is typically much stronger than other types of cannabis.

While ingesting cannabis in any form can be harmful to your physical and mental health, smoking and vaping this substance can cause serious damage to your lungs and potentially lead to a long-term illness.

Photo of a Cannabis plant.

Which chemicals are present in cannabis smoke?

Cannabis smoke has been less widely studied than tobacco smoke, but research is beginning to show the numerous harmful chemicals present in this substance.

The majority of people are aware of how harmful tobacco smoke is to the lungs, but many of the same carcinogens and chemicals are also found in cannabis smoke. [2]

When materials burn, including cannabis and filter papers, carcinogens and toxins are released through the smoke.

These are breathed in and held in the lungs before being exhaled, causing damage to the lungs.

There are thought to be up to 3000 chemicals in cannabis smoke, with many of these being toxic to your lung health.

Some studies have found that the concentrations of certain chemicals such as nitrogen oxides, hydrogen cyanide and aromatic amines are three to five times higher in cannabis smoke than those found in tobacco smoke.

Research has also shown that the amount of tar present in cannabis smoke is higher than that of tobacco smoke, which can cause serious health problems on a short or long-term basis. [3]

Other harmful chemicals present in cannabis smoke include mercury, lead, chromium, hydrogen cyanide and nickel.

Anyone who uses cannabis is exposed to the carcinogenic effects of the cannabis and filter papers as they are burned as well as the numerous chemicals contained within the cannabis itself.

What does cannabis do to the lungs?

Now that we understand more about the various chemicals, toxins and carcinogens that are present in cannabis smoke, it’s important to examine exactly how these chemicals affect the lungs.

1. Increased coughing and mucus production

Many people associated coughing and wheezing with people who regularly smoke tobacco, but you may begin to develop these symptoms as a result of smoking cannabis.

As cannabis smoke irritates the lungs and decreases lung function, you may find yourself feeling exhausted and struggling to catch your breath after even mild physical exercise.

This can prevent you from taking part in physical activities that you enjoy, and may even lead to long-term weight gain.

You may also notice an increased amount of mucus and sputum being expelled as you cough, and this is again due to the cannabis smoke causing irritation to the lining of your lungs’ airways. [3]

2. Higher risk of developing bronchitis

Bronchitis is caused by inflammation, damage and swelling in the bronchial tubes, which are the airways that let air through your lungs.

If you frequently suffer from this condition, this is known as chronic bronchitis. It can be an extremely uncomfortable illness that may make it difficult to carry out everyday tasks.

Symptoms of bronchitis can include trouble breathing, frequent coughing and a wheezing sound when they take a breath.

Studies have found a link between cannabis use and chronic bronchitis, and research suggests that people who regularly smoke cannabis are increasing their chances of developing this condition. [3]

3. Increased chances of developing lung cancer

As cannabis smoke contains a high number of carcinogens, it is likely that smoking cannabis may increase your chances of developing lung cancer.

The way cannabis is smoked may also play a role in the development of this disease as cannabis smoke is usually held in the lungs for longer than tobacco smoke, which can increase the number of particles that remain in the lungs after the smoke has been exhaled. [1]

While initial studies appear to indicate a link between smoking cannabis and developing lung cancer, more research is needed to determine the validity of these claims.

X-ray image of a ribcage.

4. Exacerbates existing lung conditions

As a plant-based substance, cannabis is more likely to cause allergy and irritation in people who are already prone to this type of reaction.

If you suffer from asthma or chronic obstructive pulmonary disease (COPD) you may find that your symptoms become worse when you smoke cannabis.

This is likely due to the irritants in the cannabis smoke or even the cannabis itself.

Even if you do not smoke cannabis yourself, being around people who smoke this substance can have a similar effect on your own lungs.

In some countries, smoking cannabis may disqualify you from certain medical treatments including lung transplants. This can have a severe effect on your long-term health and may even shorten your lifespan.

Photo of a blue asthma inhaler.

Which symptoms can indicate that cannabis is damaging my lungs?

Now that you understand the hazardous effects of cannabis on your lungs, you may be wondering whether your lungs are already showing signs of damage.

It can be difficult to know whether your lungs are healthy or not, as you are not able to see them without an invasive procedure.

However, several signs can indicate that your cannabis use is affecting your lungs and causing damage to these vital organs.

Some of the most common symptoms of lung damage caused by cannabis use include:

  • Coughing more frequently than usual, particularly hacking coughs
  • Coughing up excess mucus, sputum and phlegm
  • Struggling to breathe during and after mild physical activity
  • Inflamed, irritated and painful lungs
  • Wheezing, struggling to catch your breath

If you notice any of these symptoms appearing, it is recommended that you speak to your doctor as soon as possible.

You should also stop using cannabis in any form and refrain from vaping or smoking cigarettes, both for your lungs and your overall health.

Can secondhand cannabis smoke damage the lungs?

Photo of a man in white hat blowing cannabis smoke from a rolled cigarette.

It’s easy to believe that you can remain safe from the damaging effects of cannabis smoke if you refrain from smoking this substance yourself.

Unfortunately, being exposed to secondhand cannabis smoke can cause several effects on your own health as you are breathing in the same chemicals that are being exhaled by the smoker.

Breathing in secondhand cannabis smoke can have a hazardous effect on your lung health, as you are inhaling fine particles that contain various toxins and carcinogens.


Even though you are not actively using cannabis yourself, you may find yourself beginning to suffer from the lung damage and effects listed earlier in this article if you live or interact with someone who smokes this substance.

One study that exposed rats to secondhand cannabis smoke found that their functions were significantly impaired for up to 90 minutes after exposure, including their blood vessels and lung functioning.


Additionally, the emission rate of cannabis smoke has been found to be up to 3.5 x that of tobacco smoke.

This means that if you are living or working with someone who actively smokes cannabis, you will be exposed to a large number of the toxins and carcinogens present in the smoke.

If you are prone to respiratory conditions such as asthma, secondhand cannabis smoke can exacerbate your symptoms and potentially lead to bronchitis and pneumonia.

Does medical marijuana damage the lungs?

While cannabis is illegal in the UK and many states across America, certain people are exempt from this law.

Some research has shown a potential link between cannabis and a small number of medical conditions, and as a result, it is possible to be prescribed cannabis on a purely medical basis.

However, smoking or vaping cannabis causes damage to the lungs despite the reasons for use.

As described above, cannabis contains a large number of toxic chemicals that are released through smoke and this will continue to occur even if the use is purely medicinal. [4]

If you suffer from a condition that is being treated with the use of prescription medical marijuana, it is recommended that you speak to your doctor about alternative medical treatments that do not involve cannabis.

You may also be able to experience the potential benefits of medical cannabis through oral medication as opposed to smoking or vaping this substance.

Photograph of bald man in white shirt behind desk addressing man in black suit jacket.

Does vaping cannabis damage the lungs?

While more studies are needed to determine the effects that vaping cannabis can have on the lungs, initial research seems to indicate that it can be just as damaging as smoking.

Research has found a link between vaping cannabis and developing serious lung damage, and there have been many reports of people admitted to hospital with respiratory problems.

These reports are primarily related to those who vape THC infused cannabis and have become so prevalent that the condition is now known as e-cigarette or vaping use-associated lung injury (EVALI).

Although vaping cannabis protects you from many of the harmful chemicals found in smoke, the vape fluids themselves often contain a range of toxins and carcinogens. [3]

These may include heavy metals, artificial flavourings and ultra-fine particulates, all of which can cause serious lung damage if ingested.

Starting this behaviour from a young age can have long-term effects on the lungs caused by years of vaping cannabis, and unfortunately, many teenagers and young people have embraced vaping cannabis regularly.

Photo of a tattooed woman with shoulder length brown hair and wearing straw hat vaping.

Can your lungs recover from cannabis use?

Depending on how long you have been using cannabis, your lungs can begin to recover fairly quickly once you stop using cannabis.

You may notice a temporary increase in the amount of mucus, phlegm and tar that you cough up after quitting cannabis.

This is often a sign that your lungs are cleaning themselves and healing, and over time you should notice a reduction in this behaviour.

Your lung function should begin to improve significantly in the weeks and months after stopping your use of cannabis, and you may find that you can exert yourself physically for longer without suffering from shortness of breath.

If you have contracted a more severe illness such as pneumonia or lung cancer, there may be permanent damage caused to your lungs. It is recommended that you seek medical advice if you have found yourself in this situation.

Photo of woman with brown hair meditating on a rock facing the sea.

How to stop using cannabis

Cannabis has been proven to be psychologically addictive, so it can be extremely difficult for some people to stop using this substance.

If you are concerned about the damaging effects of cannabis on your lungs, you may want to seek professional help.

This can be in the form of a rehab centre or treatment programme, where you will receive guidance and medical support while you recover from a cannabis dependency.

Some people may need to cut down on their cannabis use gradually, while others will benefit more from quitting cold turkey.

As cannabis is not physically addictive, it is generally safe for you to completely stop using this substance, but it is recommended that you seek medical advice before taking action.

The main factor in cannabis rehab is psychological counselling which may be in the form of motivational interviewing, cognitive behavioural therapy (CBT) or acceptance and commitment therapy (ACT).

You may also benefit from alternative and holistic therapies such as mindfulness, meditation and acupuncture as part of your treatment programme.

It is common to relapse during the days, weeks or months immediately following rehab as you attempt to reintegrate back into society.

To help combat this, many rehab centres offer a complimentary 12-month aftercare programme to help you stay on track with your long-term recovery.








Boris is our editor-in-chief at Rehab 4 Addiction. Boris is an addiction expert with more than 20 years in the field.  His expertise covers a broad of topics relating to addiction, rehab and recovery. Boris is an addiction therapist and assists in the alcohol detox and rehab process. Boris has been featured on a variety of websites, including the BBC, Verywell Mind and Healthline.