OCS provides adults in Ontario with access to reliable cannabis products for responsible use and aims to help consumers separate cannabis myths from facts. If you’re unfamiliar with consuming cannabis or simply trying something new, please visit our Learn section for factual information about cannabis and cannabis consumption.
What is THC?
Short for tetrahydrocannabinol, THC is the most common cannabinoid in cannabis. It is the primary psychoactive cannabinoid responsible for the intoxicating “high” that may be experienced when it’s consumed. Learn about THC.
What is CBD?
CBD is short for cannabidiol and is another common cannabinoid in cannabis. When consumed, CBD affects various processes in your body but does not produce an intoxicating effect. Learn about CBD.
How do I know how much cannabis to consume?
Always start with a very small amount: one inhalation or a very small amount ingested. Wait at least 10 minutes before inhaling again and 60 minutes before ingesting any more. If ingesting capsules or oil, please follow the directions on the packaging. If you’re new to ingesting cannabis, consider ingesting very small amounts and waiting at least an hour to determine a product’s full effect.
The effects of cannabis vary from person to person and will also depend on the type of product and method used for consumption, along with other personal factors that can include genetics, existing mental health conditions, current mood, age, personality, gender and whether cannabis has been consumed often enough to develop a tolerance. If you’re new to consuming cannabis or looking for a milder psychoactive effect, choose products with lower THC potency or cannabis products that contain CBD. If you prefer to avoid any potential for intoxication, opt for 100% CBD products.
Can I cook with cannabis?
Yes, but it takes practice to create cannabis-infused products that are consistently dosed. You can learn more about the considerations of cooking with cannabis here. For information on safe food handling and preparation (i.e., cannabis-infused foods) please visit
Do all cannabis products make you “high”?
No. Cannabis products containing THC will have an intoxicating effect or produce a “high”. However, some cannabis products are exclusively CBD and generally have no intoxicating effects.
Is recreational cannabis different than medical cannabis?
In Ontario, recreational cannabis is only legally sold through the OCS, and medical cannabis is only available legally with a medical document from a physician or nurse practitioner through licensed sellers and Health Canada-approved at-home cultivation (visit http://laws.justice.gc.ca/eng/regulations/SOR-2016-230/ for more information on accessing medical cannabis). Products available in both channels may be different at any given time due to different distribution channels, but both are grown under regulated, quality-controlled conditions.
What is the recommended way to use cannabis?
It’s always recommended to use cannabis in moderation and to follow appropriate guidelines for consumption. When it comes to the method of consumption, consider several factors, such as health risks, the onset of effect, the duration of effect and the type of effect. For more information on suggested guidelines, click here.
What effects might I typically expect from cannabis strains with moderate THC levels?
Cannabis directly interacts with the brain and central nervous system. THC generally produces an intoxicating or impairing effect, even when very little is consumed. In moderate consumption, effects may include a sense of relaxation and pleasant euphoria. THC can also cause unpleasant or harmful effects. Senses may be heightened. The effects vary from person to person and will further depend on strain, consumption method and personal factors like genetics, existing mental health conditions, current mood, age, personality and gender.
Can cannabis have adverse effects when used with any medications?
Yes. Cannabis can have interactions with other drugs or medicinal products. Please check with your doctor or pharmacist for possible adverse effects when combining with medication.
How long will cannabis stay in my system?
This always depends on how much you consume, how you consume it and your genetics, age, personality, gender and other personal biological factors. Effects can take up to 24 hours to fully dissipate, but THC can be detectable in the bloodstream for up to seven days or more, depending on several factors, including frequency of use.
There are few reports of secondary intoxication (i.e. from second hand smoke or vape), but it also depends on a number of factors, including dose and ventilation of the space.
What should I do if I’ve consumed too much cannabis?
If you are feeling distressed, call Telehealth Ontario at 1-866-797-0000 or 1-866-797-0007 (TTY). If you’re experiencing a frighteningly rapid heartbeat, call 911.
Are there programs to help me?
How does OCS ensure that cannabis products are not sold to youth?
OCS has a strict policy of verifying the age of online visitors at the time of site entry, purchase and receipt of products.
Is second-hand smoke harmful?
Second-hand smoke is harmful, but the relationship is mediated by several factors, including the amount of smoke, frequency of use, ventilation and more. Little is factually known about the effects of cannabis smoke on lung health. However, cannabis smoke irritates the throat and lungs, and contains chemicals and tar that are similar to tobacco smoke, which can raise risks for cancer, and lung disease.
Cannabis Health & Safety
Is cannabis addictive?
It can be. Some people are more prone to becoming addicted than others, and studies suggest that using cannabis in youth increases the risk of addiction.
Approximately one in 10 adults who have ever consumed cannabis will develop an addiction, also known as “cannabis-use disorder.” The early onset of use, long-term use and combining cannabis with tobacco increase the potential of addiction and other health risks. Initiation of use in adolescence increases risk of developing cannabis use disorder to one in six.
Can I get hurt consuming cannabis?
There is no documented case of death resulting from a toxic overdose of cannabis.
However, it is possible to “overconsume” cannabis, whereby short-term and long-term adverse effects can occur, especially if you consume large amounts. Short-term adverse effects may include confusion, fatigue and anxiety, panic, paranoia,
elevated heart rate, and a significant impact to your ability to make decisions and react quickly.
The potential long-term risks include harm to your memory, decision-making ability, concentration, intelligence and mental health harms. Inhaling cannabis long term may also lead to lung damage and infections.
Driving or operating large machinery after consuming cannabis would present great risks to yourself and others. Remember that driving while impaired is against the law.
It’s also crucial to keep all cannabis products stored safely to avoid consumption by children or pets.
What are the mental health effects of cannabis use?
In some people, cannabis use increases the risk of developing mental illnesses, such as psychosis or schizophrenia. Any cannabis use is associated with a 40% increased risk of psychosis. Consuming cannabis can produce effects that induce mild or temporary symptoms of anxiety, paranoia and delusional beliefs or cause more permanent mental impairment.
Those who start using cannabis at a young age, use it daily, and have a family history of mental illness are at a greater risk. The effects and onset of these illnesses may also be worsened by using higher-strength cannabis products.
Frequent cannabis use has also been associated with an increased risk of suicide, depression and anxiety disorders. Cannabis use may also exacerbate symptoms of existing mental health problems, though further research is required.
Can I drive while or after using cannabis?
Driving while experiencing the psychoactive and intoxicating effects of cannabis containing THC is extremely dangerous. Do not drive after using cannabis, and ensure you are informed about the driving laws in Ontario. Although the effects of intoxication from cannabis that contains THC may wear off, cannabis stays in your system for some time. It is recommended that individuals who use cannabis refrain from driving (or operating other machinery or mobility devices) for at least six hours after using cannabis. If tested, you could test positive for cannabis content in your body. There are strict penalties for driving and cannabis in Ontario. For more information please visit the
Ministry of Transportation website.
Also be aware that combining alcohol and cannabis can elevate the felt effects and cause severe impairment.
Why shouldn’t tobacco be consumed with cannabis?
Tobacco is harmful on its own, and the co-use of tobacco and cannabis has been associated with developing a dependence on either substance, negative mental health outcomes, engagement in other risk-taking behaviours, and increased difficulty stopping cannabis use. There is some evidence that suggests combining tobacco with cannabis can lead to smoking initiation as well. In addition, using both substances may also lead to increased health risks compared to using just one or the other, such as the impact on the respiratory system.
Why shouldn’t alcohol be consumed with cannabis?
Combining cannabis and alcohol can elevate the felt effects and lead to extreme intoxication, dizziness and nausea. Combining cannabis with alcohol can also increase the risk of vulnerable people experiencing psychotic symptoms. Combining the two further lowers concentration and reaction times.
Are there programs to help me if I think I’ve become addicted?
Is it possible to overdose on cannabis?
Is it unhealthy to inhale cannabis smoke?
Inhaling smoke of any kind can lead to lung damage and respiratory problems. Certain smoking practices such as deep-inhalation or holding one’s breath increases these risks.
It is known that cannabis smoke contains chemicals and tar that are similar to tobacco smoke.
Does cannabis consumption lead to other drug use?
There is limited evidence that suggests cannabis use is likely to precede the use of other legal and illicit substances and the development of addiction to other substances. The majority of people who consume cannabis do not go on to use other harder substances, such as stimulants or opioids.
Can I use cannabis while pregnant or breastfeeding?
How can I reduce the risks of consuming cannabis?
Cannabis use has health risks that are best avoided by not using it. However, there are steps that can be taken that will reduce the health risks associated with use:
- Delay cannabis use until later in life
- Identify and choose safer cannabis products, like edibles (e.g., baked goods, candies or beverages that are made with cannabis)
- Avoid using synthetic cannabis (e.g., K2, Spice)
- Avoid use before operating a vehicle and wait at least six hours after using cannabis before operating a vehicle
- Avoid smoking cannabis
- Limit and reduce how often you use cannabis
Is selling medical cannabis subject to different rules than recreational cannabis?
Can I use my medical document for medical cannabis to make a purchase at OCS?
If I don’t disclose that I am purchasing for medical reasons, can I still make a purchase?
Can I give cannabis to a minor in my home?
Can I go into the United States or any other countries with my legally purchased cannabis?
No. Never cross the border with your legally purchased cannabis. Cannabis remains an illegal drug in the U.S. and many other countries, even despite some states legalizing cannabis for non-medical and medical purposes.
Where can I consume my cannabis?
Currently, you can smoke or vape your recreational and medical cannabis in your private home, in your unit or on your balcony (depending on your building rules), in many outdoor public places (like sidewalks and parks), in designated guest rooms in hotels, motels or inns, residential boats or vehicles fitted with permanent sleeping accommodations and cooking facilities when parked or anchored and meet other criteria, and in controlled areas in:
- long-term care homes
- certain retirement homes
- residential hospices
- provincially-funded supportive housing
- designated psychiatric facilities or veterans’ facilities
However, other laws and policies may apply to restrict cannabis use in these places, such as municipal by-laws, condo by-laws, lease agreements, and the policies of employers and property owners.
What places are not permitted for cannabis consumption?
Under Ontario law, Cannabis cannot be smoked or vaped in:
- Enclosed public places and enclosed workplaces
- Indoor common areas in condominiums, apartment buildings and university/college residences
- Schools and school grounds, and public areas within 20 metres of those grounds
- Outdoor grounds of a community recreational facility, and public areas within 20 metres of those grounds
- Child care centres, and places where an early years program or services is provided
- Places where home child care is provided, regardless of whether children are present
- Children’s playgrounds and public areas within 20 metres of playgrounds
- Publicly-owned sporting areas (not including golf courses), adjacent spectator areas and public areas within 20 metres of these areas
- Vehicles and boats that are being driven or under someone’s care or control
- Restaurant and bar patios and public areas within nine metres of a patio (this applies to all forms of consumption, except non-smoking and non-vaping consumption by a medical cannabis)
- Nine meters from the entrance or exit of a public hospital, private hospital, psychiatric facility, long-term care home and independent health facility
- Outdoor grounds of public hospitals, private hospitals and psychiatric facilities
- Outdoor grounds of certain Ontario Government office buildings
- Reserved seating areas of outdoor sports or entertainment venues
- Outdoor sheltered areas with a roof and more than two walls to which the public is invited or employees frequent (e.g. bus shelter)
Any method of consuming cannabis (smoking, vaping, ingestion) will also be prohibited in vehicles and boats that are being driven or under a person’s care or control, even when not in motion.
Can I purchase seeds or clones at OCS for growing my own cannabis at home?
By Ontario law, you are permitted to grow up to four plants in your home for personal use. OCS sells various types of seeds for this purpose and will not sell clones at this time.
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