It’s time to talk about:

Cannabis

Did You Know?

Smoking is the most common way that people use cannabis, and one of the most harmful.

Cannabis Resources:

Download Cannabis Harm Reduction Printable Pocket Cards (PDF)

Cannabis for Health Professionals

Smoking cannabis, no matter how it’s done, exposes the lungs to harmful toxins and carcinogens, similar to those found in tobacco smoke. These substances can cause lung irritation, chronic bronchitis, and may increase the risk of respiratory infections or more serious health issues over time.

For those who use cannabis, exploring less harmful methods of consumption—such as edibles or oils — can significantly reduce risks to lung health.

Did You Know! (Based on 2024 Canadian Cannabis Statistics)

most people are not using daily

more than half use 3 days/month or less

most users do not drive after using

The average person spent $63 per month on cannabis in 2024

Know your Product

Understanding Cannabis Effects

This graph visually depicts the effects of cannabis through various consumption methods, highlighting the times of onset, maximum intensity reached, how long effects last.

Cannabis: Know the Risks

Smoking

Toxic Smoke: Smoke from burning cannabis contains harmful substances similar to those found in tobacco smoke.³⁴
Deep Inhalation: Cannabis smokers tend to breathe in deeply and hold their breath longer than cigarette smokers, leading to increased tar exposure.³⁴
Respiratory Issues: People who smoke cannabis frequently, without mixing it with tobacco, often have more visits to healthcare providers for respiratory problems compared to non-smokers.³⁰

Vaping

Weakened Immune System: Vaping cannabis can make the immune system weaker and increase the risk of lung infections.³⁴
Perceived Safety: Some people believe vaping is safer for the lungs than smoking, which might lead to more frequent use or starting cannabis use earlier, increasing the risk of problematic use or addiction.³³, ⁴²

Edibles

Accidental Ingestion: There is a risk of children accidentally eating cannabis edibles, which can be dangerous.³
More intense effects: Longer and more intense psychoactive effects (THC)⁷, ⁸, ¹⁰, ¹³
Delayed onset: Edibles take a while to kick in, which can make people eat too much before they feel anything.⁷, ⁸, ¹⁰, ¹³

Oils

Drug Interactions: Since both THC and CBD are processed by the liver, there’s a chance they could interact with other medications, affecting how they work in the body.¹⁵
Hard to dose: Oils can be hard to dose (volume and potency vary a lot).

Protect Your Lungs

This table shows how different cannabis products affect lung health, from higher risk to lower risk. It highlights that smoking and vaping are hardest on the lungs.

Transitioning Away From Smoking: Edibles and Oils

Switching to edibles and oils can be better for your lungs.²³
Choose Low THC and Higher CBD: Products with low THC and an equal or higher amount of CBD are recommended.¹²
Benefits of CBD: CBD can reduce the side effects of THC, especially useful during the day or when driving.¹²
Medication Interactions: THC and CBD can interact with some medications.¹² ¹⁵
- Example 1: CBD can affect how clobazam, a medication for seizures, is processed.¹² ¹⁵
- Example 2: Cannabis can also affect warfarin, a blood thinner, making it work more strongly.¹⁹
Medical vs. Recreational Use: Medical cannabis patients often use products with more CBD and less THC to improve symptoms, function, and quality of life, with fewer side effects.¹²

Start Low, Go Slow

When starting with cannabis, it’s best to “start low, go slow, and stay low.”

Smoking/vaping: 1–2 puffs of 10% THC or less, then wait 15 minutes to feel effects. Add 1 puff every 15–30 minutes if needed. ¹² ³²
Consider safer alternatives like edibles and oils for lung health, and be aware of how cannabis might interact with other medications.
Edibles: Start with 2.5 mg of THC or less.¹² ³²
Choose Low THC and Higher CBD: Products with low THC and equal or higher CBD are recommended.¹²
Sublingual Sprays: These offer precise dosing, better absorption, and a quick effect similar to smoking or vaping.⁸ ¹²
Be Aware of Drug Interactions: Learn how cannabis may interact with other medications you are taking. Learn about drug interactions and cannabis.

Cannabis in your Life

Cannabis can affect different parts of daily life. Here are some common risks and practical ways to reduce harm.

Health

LUNGS

Smoking cannabis exposes your lungs to harmful chemicals and can irritate your airways. ²⁷, ²⁸, ²⁹, ³⁴, ³⁰

Lower-risk tip: Avoid deep inhaling or holding your breath to reduce lung exposure and consider non-smoking options

MENTAL HEALTH

Regular use, especially high THC, is linked to increased long-term risk of experiencing anxiety, depression, schizophrenia, and other mental health problems. ¹³, ¹⁴, ¹⁵, ⁵⁶, ⁷⁸, ⁷⁹, ⁸⁰

Lower-risk tip: Choose lower-THC or balanced THC:CBD products and avoid frequent use.

HEART HEALTH

Smoking cannabis can put extra strain on the heart and lungs, especially for people with existing health concerns.¹⁶,¹⁷, ³¹,³², ⁵⁶, ⁸¹, ⁸², ⁹⁶, ⁹⁷

Lower-risk tip: Avoiding or reducing smoked cannabis products can help reduce harm.

SLEEP

Cannabis may help you fall asleep faster at first, but regular use can affect sleep quality over time and make it harder to sleep without it.¹²², ¹²⁵, ¹²⁶

Lower-risk tip: Avoid making it a nightly habit, choose lower-THC products, and build a bedtime routine that does not rely on cannabis.

MEDICATIONS

Cannabis can interact with some medications and change how they work. This may increase side effects or affect how well a medicine works.⁵, ⁵⁶, ⁷⁰, ⁸³

Lower-risk tip: If you use cannabis for medical or non-medical reasons, talk to a health care provider or pharmacist.
Medications that may interact with cannabis include¹³³:

ADHD medications
allergy medications
antibiotics and antifungal medications
antidepressant or anti-anxiety medications
anti-seizure medications
blood thinners
cold and flu medications
heart medications
HIV medications
pain medications
sleeping pills

Daily Life

Work & School

Frequent cannabis use, especially high-THC products, can affect memory, learning, and attention in the long-term. ⁸³, ⁶⁶, ⁶⁷, ⁶⁸, ⁶⁹, ⁷¹, ⁷², ⁷³, ⁸³

Lower-risk tip: Avoid using before work or school, use less often, and choose lower-THC or balanced THC:CBD products.

Driving

Cannabis can slow reaction time and affect focus, coordination, and judgment, making driving or operating equipment less safe. These effects can last from 6 to 24 hours, depending on the dose. Higher doses may cause effects to last longer. ¹⁰,¹¹,¹², ⁵⁶

Lower-risk tip: Plan a safe ride home and avoid driving or using heavy equipment for at least 6 hours, and longer if you still feel impaired.

Mixing Substances

Mixing cannabis with alcohol or other drugs can increase impairment and make effects less predictable. ⁷⁴, ⁹³, ¹⁰⁹, ¹¹⁰, ¹²⁹, ¹³⁰

Lower-risk tip: Stick to one substance, or use less if mixing.

Other Considerations: Cannabis & Reproductive Health

Using cannabis during pregnancy can harm reproductive systems and early childhood development. Due to limited research, it’s best to be cautious with cannabis use during pregnancy to avoid risks to the baby.

Know the Reproductive Risks

Cannabis & Pregnancy

Using cannabis during pregnancy can harm female reproductive systems and early childhood development. Due to limited research, it’s best to be cautious with cannabis use during pregnancy to avoid risks to the baby.
Cannabis can affect hormones and reproduction, potentially disrupting menstrual cycles and ovulation.
THC can remain in the body for up to 30 days after stopping use.
Many pregnancies are unplanned, so women may unknowingly use cannabis early in pregnancy.
THC crosses the placenta and can decrease fetal folic acid, essential for development, leading to risks like miscarriages and low birth weight.
Cannabis use during pregnancy can impair a child’s memory, learning, and other cognitive functions.
Passive exposure to cannabis smoke can also affect pregnant women and their babies.

Cannabis and Breastfeeding

THC can remain in breast milk for weeks and be more concentrated than in the mother’s blood.
Babies exposed to THC through breast milk may experience drowsiness, reduced muscle tone, and poor feeding, impacting their nutrition.

Cannabis and Male Infertility

Cannabis use can lead to poor sperm quality, lower sperm count, and higher rates of erectile dysfunction.
THC can interfere with important reproductive processes like sperm maturation.

Want to learn more about Cannabis?