Medical marijuana has been legal for some time in Canada, with restrictions that vary from province to province. Recreational use of marijuana has been legal since 2018; however, there are restrictions varying by province on how much can be purchased at one time, where cannabis products can legally be purchased, which cannabis products can legally be purchased, and how many cannabis plants can be grown at home. Edibles were legalized in 2019.

Importation and exportation remain illegal. See Cannabis and international travel on the Government of Canada's website for details.

While cannabis remains illegal in India, some traditional forms of usage are allowed. One of them is bhang thandai, also known as bhang lassi, an infusion of cannabis paste (buds and leaves) and various nuts, herbs and spices in milk that is available in government authorised shops in parts of the subcontinent, including the states of Rajasthan, Uttar Pradesh, and Bihar.

While it has never been legalized, cannabis and a handful of other substances disallowed elsewhere can be bought in "coffee shops" that are legal. The issue of "drug-tourism", however, is somewhat controversial, so there may be some restrictions on foreigners frequenting coffee shops or buying cannabis products there. Cannabis products with no THC content are legal even outside coffee shops.

While cultivation and possession for private use is legal in Spain, selling the drug is a crime.

Long infamous for its extremely strict drug laws, Thailand did a drastic U-turn in 2018 when it became the first country in Southeast Asia to legalize medical cannabis (กัญชา ganchaa), expanding this in 2022 to legalize recreational use as well. While extracts of cannabis including all edibles are limited to under 0.2% THC, there are no limits on the potency of plant parts like flowers, leaves or stems. Consumption in public is not permitted, but is now legal in private homes and any spaces like cafes and bars that choose to allow it.

Vaping, importing and exporting all remain illegal.

Several states have legalized use or possession of cannabis. While federal law prohibits possession, federal authorities do in practice not pursue intrastate users who abide by state laws, and aren't allowed to regarding medical use. Jurisdictions where recreational use of cannabis is allowed include Alaska, Arizona, California, Colorado, Illinois, Maine, Massachusetts, Michigan, Montana, Nevada, New Jersey, New Mexico, New York, Oregon, Vermont, Virginia, Washington State, Washington, D.C. and the U.S. territory of Guam. Several more have medical marijuana laws of varying strictness.

All jurisdictions that have legalized allow for the commercial distribution of cannabis, except Vermont and Washington, D.C. – but marijuana-related businesses are routinely denied access to the banking system, so expect to pay cash.

As the constitution explicitly grants the federal government the right to regulate interstate commerce, carrying cannabis across state lines – even between two states where it is legal – is a federal matter and illegal. Cannabis possession is likewise illegal on some native reservations and all federal enclaves (e.g. airport security, as the TSA is a federal agency), even when surrounded by states where it is otherwise legal.

Customs remains a magical rights-free zone where possession of even a single copy of High Times magazine (protected by the US First Amendment as free speech anywhere else) is grounds enough for an agent to ask if you've ever used marijuana and ban you from the country for a very long time, maybe forever (unless you're a U.S. citizen, in which case you can't be banned from entry, but the magazine is grounds for an extremely intrusive search).

As of 2019, CBD (cannabidiol) products, as long as they contain no more than a very small amount of THC, are at least nominally legal under federal law, as well as in most states. However, because the federal government has yet to issue regulations to fully implement this change, some states continue to ban CBD and hemp products, even prosecuting truckers for transporting hemp that is nominally legal under federal law.

Cannabis products are legal in Uruguay. The law states that buyers have to be over 18 and legal residents of Uruguay, but this is enforced inconsistently at most; less formal vendors like farmers' market stands don't often check IDs.

See also: Medication

As of 2018, some new prescription medications carefully extract and package just one active ingredient derived from cannabis. For instance, Epidiolex is a purified form of cannabidiol (CBD, one of hundreds of molecules found in marijuana) developed as a treatment for childhood epilepsy.

The legality of these products varies widely internationally; they may be lawfully-regulated prescription medicine in one country, criminalised as illegal street drugs in another, and pending lengthy clinical trials before they can be sold and prescribed somewhere else. Any attempt to carry this medicine into another country is a legal minefield to be avoided at all costs, even if the product is lawful and regulated at its point of origin.

Cannabis usage can be detected through testing of urine, blood and hair samples. While blood and hair testing requires time and laboratory equipment, urine testing can be done on the spot with cheap and reliable test strips.

Detection times depend on the amount consumed, the consumption frequency, the quality of the material and the metabolism of the person. Compared to other drugs, traces of cannabis can be detected long after the last consumption. It can be difficult to tell how long after the last consumption a test will show a "positive" result, but generally the detection times for the most common test kit (20 ng/mL cut off) are:

• Up to 7 days for a one time user
• Up to 30 days for a regular weekend user
• Up to 80 days for a heavy user

These are examples and should not be used to declare someone "clean" under any circumstances. Cannabis detection times are unpredictable. If in doubt, play it safe.

In some countries, perhaps most notoriously China and Singapore, testing positive is all it takes to get you in trouble, even if you can prove that it was consumed outside the country in a jurisdiction where it is legal. Dubai has a reputation of zero tolerance, with 2 years of imprisonment for peeing positive. In China, testing positive can lead to administration detention up to 15 days with compulsory rehabilitation and deportation. Countries like South Korea and Singapore also have extraterritorial laws to prosecute their own citizens who consume cannabis in foreign countries, even if cannabis is legal in such foreign countries.

In the United Kingdom, driving after consuming cannabis can be extremely legally risky even if you are not impaired, since the legal limits for driving with THC in one's system are exceptionally low, being 2 micrograms per litre of blood; this will easily be exceeded by someone who has recently consumed the drug even if they are not impaired at all, while a habitual consumer may not be "clean" by these standards for weeks. In the event of an accident, there is every chance you could be drug swabbed, and if positive you are likely to be arrested and charged (refusing the swab carries the same penalty as failing it). If you are intent on driving in the UK, the best thing to do is simply not to consume cannabis.

If you choose to take the risk, stay below the radar. Dress decent and avoid that stereotypical stoner look.