Cannabis (), commonly known as marijuana (), weed, pot, and ganja, among other names, is a non-chemically uniform psychoactive drug from the Cannabis plant. Native to Central or South Asia, cannabis has been used as a drug for both recreational and entheogenic purposes and in various traditional medicines for centuries. Tetrahydrocannabinol (THC) is the main psychoactive component of cannabis, which is one of the 483 known compounds in the plant, including at least 65 other , such as cannabidiol (CBD). Cannabis can be used Cannabis smoking, vaporizing, Cannabis edible, or as an extract.
Cannabis has various mental and physical effects, which include euphoria, altered states of mind and sense of time, difficulty concentrating, impaired short-term memory, impaired motor skill (balance and fine psychomotor control), relaxation, and an increase in appetite. Onset of effects is felt within minutes when smoked, but may take up to 90 minutes when eaten (as orally consumed drugs must be digested and absorbed). The effects last for two to six hours, depending on the amount used. At high doses, mental effects can include anxiety, delusions (including ideas of reference), , panic attack, paranoia, and psychosis. There is a strong relation between cannabis use and the risk of psychosis, though the direction of causality is debated. Physical effects include increased heart rate, difficulty breathing, nausea, and behavioral problems in children whose mothers used cannabis during pregnancy; short-term side effects may also include xerostomia and red eyes. Long-term adverse effects may include addiction, decreased neurocognition in those who started regular use as adolescents, chronic coughing, susceptibility to respiratory infections, and cannabinoid hyperemesis syndrome.
Cannabis is mostly used recreationally or as a medicinal drug, although it may also be used for spiritual purposes. In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65). It is the most commonly used largely-illegal drug in the world, with the highest use among adults in Zambia, the United States, Canada, and Nigeria. Since the 1970s, the potency of illicit cannabis has increased, with THC levels rising and CBD levels dropping.
Cannabis plants have been grown since at least the 3rd millennium BCE and there is evidence of it being smoked for its psychoactive effects around 500 BCE in the Pamir Mountains, Central Asia. Since the 14th century, cannabis has been subject to legal restrictions. The possession, use, and cultivation of cannabis has been illegal in most countries since the 20th century. In 2013, Uruguay became the first country to legalize recreational use of cannabis. Other countries to do so are Canada, Georgia, Germany, Luxembourg, Malta, South Africa, and Thailand. In the U.S., the recreational use of cannabis is legalized in 24 states, 3 territories, and the District of Columbia, though the drug remains federally illegal. In Australia, it is legalized only in the Australian Capital Territory.
The medical use of cannabis is legal only in a limited number of territories, including Canada, Belgium, Australia, the Netherlands, New Zealand, Spain, and many U.S. states. This usage generally requires a prescription, and distribution is usually done within a framework defined by local laws.
Additional desired effects from consuming cannabis include relaxation, a general alteration of conscious perception, increased awareness of sensation, increased libido and distortions in the perception of time and space. In some cases, cannabis can lead to dissociative states such as depersonalization and derealization.
In modern culture, the spiritual use of cannabis has been spread by the disciples of the Rastafari movement who use cannabis as a sacrament and as an aid to meditation.
In 2018, surveys indicated that almost half of the people in the United States had tried marijuana, 16% had used it in the past year, and 11% had used it in the past month. In 2014, surveys said daily marijuana use amongst US college students had reached its highest level since records began in 1980, rising from 3.5% in 2007 to 5.9% in 2014 and had surpassed daily cigarette use.
In the US, men are over twice as likely to use marijuana as women, and 1829-year-olds are six times more likely to use as over-65-year-olds. In 2015, a record 44% of the US population has tried marijuana in their lifetime, an increase from 38% in 2013 and 33% in 1985.
Marijuana use in the United States is three times above the global average, but in line with other Western democracies. Forty-four percent of American 12th graders have tried the drug at least once, and the typical age of first-use is 16, similar to the typical age of first-use for alcohol but lower than the first-use age for other illicit drugs.
A 2022 Gallup poll concluded Americans are smoking more marijuana than cigarettes for the first time.
Some immediate undesired side effects include a decrease in short-term memory, dry mouth, impaired motor skills, reddening of the eyes, dizziness, feeling tired and vomiting. Some users may experience an episode of acute psychosis, which usually abates after six hours, but in rare instances, heavy users may find the symptoms continuing for many days.
Legalization has increased the rates at which children are exposed to cannabis, particularly from edibles. While the toxicity and lethality of THC in children is not known, they are at risk for encephalopathy, hypotension, respiratory depression severe enough to require ventilation, somnolence and coma.
A 16-month survey of Oregon and Alaska emergency departments found a report of the death of an adult who had been admitted for acute cannabis toxicity.
A recent study in 2025 suggests that individuals diagnosed with cannabis use disorder—characterized by an inability to stop using cannabis despite its negative effects—face a nearly threefold increase in compared to those without the condition over a five-year period. The research indicates that people with this disorder are ten times more likely to die by suicide than the general population. Additionally, they have a higher risk of death from trauma, drug poisoning, and lung cancer. In a separate study researchers found an increase in schizophrenia and psychosis cases in Canada linked to cannabis use disorder following the drug’s legalization.
A reduced quality of life is associated with heavy cannabis use, although the relationship is inconsistent and weaker than for tobacco and other substances. The direction of cause and effect, however, is unclear.
The long-term effects of cannabis are not clear. There are concerns surrounding memory and cognition problems, risk of addiction, and the risk of schizophrenia in young people.
Cannabis use is associated with increased recruitment of task-related areas, such as the dorsolateral prefrontal cortex, which is thought to reflect compensatory activity due to reduced processing efficiency. Cannabis use is also associated with downregulation of CB1 receptors. The magnitude of down regulation is associated with cumulative cannabis exposure, and is reversed after one month of abstinence. There is limited evidence that chronic cannabis use can reduce levels of glutamate metabolites in the human brain.
According to DSM-5 criteria, 9% of those who are exposed to cannabis develop cannabis use disorder, compared to 20% for cocaine, 23% for alcohol and 68% for nicotine. Cannabis use disorder in the DSM-5 involves a combination of DSM-IV criteria for cannabis abuse and dependence, plus the addition of craving, without the criterion related to legal troubles.
At an epidemiological level, a dose–response relationship exists between cannabis use and increased risk of psychosis and earlier onset of psychosis. Although the epidemiological association is robust, evidence to prove a causal relationship is lacking.
Cannabis may also increase the risk of depression, but insufficient research has been performed to draw a conclusion. Cannabis use is associated with increased risk of anxiety disorders, although causality has not been established.
A review in 2019 found that research was insufficient to determine the safety and efficacy of using cannabis to treat schizophrenia, psychosis, or other . Another found that cannabis during adolescence was associated with an increased risk of developing depression and suicidal behavior later in life, while finding no effect on anxiety.
Cannabinoid hyperemesis syndrome (CHS) is a severe condition seen in some chronic cannabis users where they have repeated bouts of uncontrollable vomiting for 24–48 hours.
Four cases of death have been reported as a result of CHS.
A limited number of studies have examined the effects of cannabis smoking on the respiratory system. Chronic heavy marijuana smoking is associated with respiratory infections, coughing, production of sputum, wheezing, and other symptoms of chronic bronchitis. The available evidence does not support a causal relationship between cannabis use and chronic obstructive pulmonary disease. Short-term use of cannabis is associated with bronchodilation. Other side effects of cannabis use include cannabinoid hyperemesis syndrome (CHS), a condition which involves recurrent nausea, cramping abdominal pain, and vomiting.
Cannabis smoke contains thousands of organic and inorganic chemical compounds. This tar is chemically similar to that found in tobacco smoke, and over fifty known have been identified in cannabis smoke, including; nitrosamines, reactive aldehydes, and polycyclic aromatic hydrocarbons, including benzapyrene. Cannabis smoke is also inhaled more deeply than tobacco smoke. , there is no consensus regarding whether cannabis smoking is associated with an increased risk of cancer. Light and moderate use of cannabis is not believed to increase risk of lung or upper airway cancer. Evidence for causing these cancers is mixed concerning heavy, long-term use. In general there are far lower risks of pulmonary complications for regular cannabis smokers when compared with those of tobacco. A 2015 review found an association between cannabis use and the development of testicular germ cell tumors (TGCTs), particularly non-seminoma TGCTs. Another 2015 meta-analysis found no association between lifetime cannabis use and risk of head or neck cancer. Combustion products are not present when using a vaporizer, consuming THC in pill form, or consuming cannabis foods.
There is concern that cannabis may contribute to cardiovascular disease, but , evidence of this relationship was unclear. Research in these events is complicated because cannabis is often used in conjunction with tobacco, and drugs such as alcohol and cocaine that are known to have cardiovascular risk factors. Smoking cannabis has also been shown to increase the risk of myocardial infarction by 4.8 times for the 60 minutes after consumption.
There is preliminary evidence that cannabis interferes with the anticoagulant properties of prescription drugs used for thrombosis. , the mechanisms for the anti-inflammatory and possible Analgesic effects of cannabis were not defined, and there were no governmental regulatory approvals or clinical practices for use of cannabis as a drug.
According to the United States Department of Health and Human Services, there were 455,000 emergency room visits associated with cannabis use in 2011. These statistics include visits in which the patient was treated for a condition induced by or related to recent cannabis use. The drug use must be "implicated" in the emergency department visit, but does not need to be the direct cause of the visit. Most of the illicit drug emergency room visits involved multiple drugs. In 129,000 cases, cannabis was the only implicated drug.
Via CB1 receptor activation, THC indirectly increases dopamine release and produces psychotropic effects. Cannabidiol also acts as an allosteric modulator of the μ- and δ-opioid receptors. THC also potentiates the effects of the . It is unknown if or how these actions contribute to the effects of cannabis.
The Duquenois–Levine test is commonly used as a screening test in the field, but it cannot definitively confirm the presence of cannabis, as a large range of substances have been shown to give false positives. Researchers at John Jay College of Criminal Justice reported that dietary zinc supplements can mask the presence of THC and other drugs in urine. However, a 2013 study conducted by researchers at the University of Utah School of Medicine refute the possibility of self-administered zinc producing false-negative urine drug tests.
A 2015 review found that the use of high CBD-to-THC strains of cannabis showed significantly fewer positive symptoms, such as delusions and hallucinations, better cognitive function and both lower risk for developing psychosis, as well as a later age of onset of the illness, compared to cannabis with low CBD-to-THC ratios.
Studies have found that the potency of illicit cannabis has greatly increased since the 1970s, with THC levels rising and CBD levels dropping. It is unclear, however, whether the increase in THC content has caused people to consume more THC or if users adjust based on the potency of the cannabis. It is likely that the higher THC content allows people to ingest less tar. At the same time, CBD levels in seized samples have lowered, in part because of the desire to produce higher THC levels and because more illegal growers cultivate indoors using artificial lights. This helps avoid detection but reduces the CBD production of the plant.
Australia's National Cannabis Prevention and Information Centre (NCPIC) states that the buds () of the female Cannabis plant contain the highest concentration of THC, followed by the leaves. The stalks and seeds have "much lower THC levels". The UN states that the leaves can contain ten times less THC than the buds, and the stalks 100 times less THC.
After revisions to cannabis scheduling in the UK, the government moved cannabis back from a class C to a class B drug. A purported reason was the appearance of high potency cannabis. They believe skunk accounts for between 70% and 80% of samples seized by police (despite the fact that skunk can sometimes be incorrectly mistaken for all types of herbal cannabis). such as hashish and hash oil typically contain more THC than high potency cannabis infructescences.
The short-term effects of cannabis can be altered if it has been laced with opioid drugs such as heroin or fentanyl. "Growing Array of Street Drugs Now Laced with Fentanyl", MedPageToday, 17 July 2018 The added drugs are meant to enhance the psychoactive properties, add to its weight, and increase profitability, despite the increased danger of overdose. "Is the opioid epidemic now the fentanyl epidemic?" , The Baltimore Sun, 7 December 2018
Cannabis was known to the ancient Assyrians, who discovered its psychoactive properties through the Iranians. Using it in some religious ceremonies, they called it qunubu (meaning "way to produce smoke"), a probable origin of the modern word cannabis. The Iranians also introduced cannabis to the Scythians, Thracians and , whose shamans (the kapnobatai"those who walk on smoke/clouds") burned cannabis infructescences to induce trance. The plant was used in China before 2800 BC, and found therapeutic use in India by 1000 BC, where it was used cannabis edible, including bhang.
Cannabis has an ancient history of ritual use and has been used by religions around the world. It has been used as a drug for both recreational and entheogenic purposes and in various traditional medicines for centuries.See also article on Marijuana as a word. The earliest evidence of cannabis smoking has been found in the 2,500-year-old tombs of Jirzankal Cemetery in the Pamir Mountains in Western China, where cannabis residue were found in burners with charred pebbles possibly used during funeral rituals. Hemp seeds discovered by archaeologists at Pazyryk burials suggest early ceremonial practices like eating by the Scythians occurred during the 5th to 2nd century BC, confirming previous historical reports by Herodotus. It was used by Muslims in various Sufi orders as early as the Mamluk period, for example by the Qalandariyya. Smoking pipes uncovered in Ethiopia and carbon-dated to around AD 1320 were found to have traces of cannabis.
Cannabis was criminalized in some countries beginning in the 14th century and was illegal in most countries by the middle of the 20th century. The colonial government of Mauritius banned cannabis in 1840 over concerns on its effect on Indian indentured workers; the same occurred in Singapore in 1870. In the United States, the first restrictions on sale of cannabis came in 1906 (in the District of Columbia). Canada criminalized cannabis in The Opium and Narcotic Drug Act, 1923, before any reports of the use of the drug in Canada, but eventually legalized its consumption for recreational and medicinal purposes in 2018.
In 1925, a compromise was made at an international conference in The Hague about the International Opium Convention that banned exportation of "Indian hemp" to countries that had prohibited its use, and requiring importing countries to issue certificates approving the importation and stating that the shipment was required "exclusively for medical or scientific purposes". It also required parties to "exercise an effective control of such a nature as to prevent the illicit international traffic in Indian hemp and especially in the resin". In the United States in 1937, the Marihuana Tax Act was passed, and prohibited the production of hemp in addition to cannabis.
In 1972, the Dutch government divided drugs into more- and less-dangerous categories, with cannabis being in the lesser category. Accordingly, possession of or less was made a misdemeanor. Cannabis has been available for recreational use in coffee shops since 1976. Cannabis products are only sold openly in certain local "coffeeshops" and possession of up to for personal use is decriminalized, however: the police may still confiscate it, which often happens in car checks near the border. Other types of sales and transportation are not permitted, although the general approach toward cannabis was lenient even before official decriminalization.
In Uruguay, President Jose Mujica signed legislation to legalize recreational cannabis in December 2013, making Uruguay the first country in the modern era to legalize cannabis. In August 2014, Uruguay legalized growing up to six plants at home, as well as the formation of growing clubs (Cannabis social club), and a state-controlled marijuana dispensary regime.
, when recreational use of cannabis was legalized in Canada, dietary supplements for human use and veterinary health products containing not more than 10 parts per million of THC extract were approved for marketing; Nabiximols (as Sativex) is used as a prescription drug in Canada.
The United Nations' World Drug Report stated that cannabis "was the world's most widely produced, trafficked, and consumed drug in the world in 2010", and estimated between 128 million and 238 million users globally in 2015.
Since the beginning of the 20th century, most countries have enacted laws against the cultivation, possession or transfer of cannabis. These laws have had an adverse effect on cannabis cultivation for non-recreational purposes, but there are many regions where handling of cannabis is legal or licensed. Many jurisdictions have lessened the penalties for possession of small quantities of cannabis so that it is punished by confiscation and sometimes a fine, rather than imprisonment, focusing more on those who traffic the drug on the black market.
In some areas where cannabis use had been historically tolerated, new restrictions were instituted, such as the closing of cannabis coffee shops near the borders of the Netherlands, and closing of coffee shops near secondary schools in the Netherlands. "43 Amsterdam coffee shops to close door", Radio Netherlands, Friday 21 November 2008 In Copenhagen, Denmark in 2014, mayor Frank Jensen discussed possibilities for the city to legalize cannabis production and commerce.
Some jurisdictions use free voluntary or mandatory treatment programs for frequent known users. Simple possession can carry long prison terms in some countries, particularly in East Asia, where the sale of cannabis may lead to a sentence of life in prison or even execution. Political parties, non-profit organizations, and causes based on the legalization of medical cannabis or legalizing the plant entirely (with some restrictions) have emerged in such countries as China and Thailand.
In December 2012, the U.S. state of Washington became the first state to officially legalize cannabis in a state law (Washington Initiative 502) (but still illegal by federal law), with the state of Colorado following close behind (Colorado Amendment 64). On 1 January 2013, the first cannabis "club" for private marijuana smoking (no buying or selling, however) was allowed for the first time in Colorado. The California Supreme Court decided in May 2013 that local governments can ban medical cannabis dispensaries despite a state law in California that permits the use of cannabis for medical purposes. At least 180 cities across California have enacted bans in recent years. discussess rescheduling of cannabis.]]
On 30 April 2024, the United States Department of Justice announced it would move to reclassify cannabis from a Schedule I to a Schedule III controlled substance.
In December 2013, Uruguay became the first country to legalize growing, sale and use of cannabis. After a long delay in implementing the retail component of the law, in 2017 sixteen pharmacies were authorized to sell cannabis commercially. On 19 June 2018, the Canadian Senate passed a bill and the Prime Minister announced the effective legalization date as 17 October 2018. Canada is the second country to legalize the drug.
In November 2015, Uttarakhand became the first state of India to legalize the cultivation of hemp for industrial purposes. Usage within the Hindu and Buddhist cultures of the Indian subcontinent is common, with many street vendors in India openly selling products infused with cannabis, and traditional medical practitioners in Sri Lanka selling products infused with cannabis for recreational purposes and well as for religious celebrations. Indian laws criminalizing cannabis date back to the Colonial India. India and Sri Lanka have allowed cannabis to be taken in the context of traditional culture for recreational/celebratory purposes and also for medicinal purposes.
On 17 October 2015, Australian health minister Sussan Ley presented a new law that will allow the Agriculture of cannabis for scientific research and medical trials on patients.Alchimia Blog, Medical marijuana news, December 2015
On 17 October 2018, Canada legalized cannabis for recreational adult use making it the second country in the world to do so after Uruguay and the first G7 nation. This legalization comes with regulation similar to that of alcohol in Canada, age restrictions, limiting home production, distribution, consumption areas and sale times. Laws around use vary from province to province including age limits, retail structure, and growing at home. The Canadian Licensed Producer system aims to become the Gold Standard in the world for safe and secure cannabis production, including provisions for a robust craft cannabis industry where many expect opportunities for experimenting with different strains.
As the drug has increasingly been seen as a health issue instead of criminal behavior, cannabis has also been legalized or decriminalized in: Czech Republic, " Podle čl. 36 Jednotné úmluvy o omamných látkách ze dne 31. března 1961 (č. 47/1965 Sb.) se signatáři zavazují k trestnímu postihu tam uvedených forem nakládání s drogami včetně jejich držby. Návrh upouští od dosavadní beztrestnosti držby omamných a psychotropních látek a jedů pro svoji potřebu. Dosavadní beztrestnost totiž eliminuje v řadě případů možnost postihu dealerů a distributorů drog." Colombia, Ecuador, "Dosis máximas de droga para consumo ya están vigentes" at El Comercio.com. "Ecuador: Aprueban tenencia de drogas para consumo" at El Nuevo Herald Portugal, South Africa and Canada. Medical marijuana was legalized in Mexico in mid-2017 and legalized for recreational use in June 2021.
Germany legalized cannabis for recreational use in April 2024.
Penalties for illegal recreational use ranges from confiscation or small fines to jail time and even death. In some countries, citizens can be punished if they have used the drug in another country, including Singapore and South Korea.
"Skunk" refers to several named strains of potent cannabis, grown through selective breeding and sometimes hydroponics. It is a cross-breed of Cannabis sativa and C. indica (although other strains of this mix exist in abundance). Skunk cannabis potency ranges usually from 6% to 15% and rarely as high as 20%. The average THC level in coffee shops in the Netherlands is about 18–19%. Ch. 2.3.
The average levels of THC in cannabis sold in the United States rose dramatically between the 1970s and 2000. This is disputed for various reasons, and there is little consensus as to whether this is a fact or an artifact of poor testing methodologies. According to Daniel Forbes writing for slate.com, the relative strength of modern strains are likely skewed because undue weight is given to much more expensive and potent, but less prevalent, samples. Some suggest that results are skewed by older testing methods that included low-THC-content plant material such as leaves in the samples, which are excluded in contemporary tests. Others believe that modern strains actually are significantly more potent than older ones.
The main producing countries of cannabis are Afghanistan, Canada, China, Colombia, India, Jamaica, Lebanon, Mexico, Morocco, the Netherlands, Pakistan, Paraguay, Spain, Thailand, Turkey, the United Kingdom, and the United States.
After some U.S. states legalized cannabis, street prices began to drop. In Colorado, the price of smokable buds (infructescences) dropped 40 percent between 2014 and 2019, from $200 per ounce to $120 per ounce ($7 per gram to $4.19 per gram).
The European Monitoring Centre for Drugs and Drug Addiction reports that typical retail prices in Europe for cannabis varied from €2 to €20 per gram in 2008, with a majority of European countries reporting prices in the range €4–10.
Some studies state that while there is no proof for the gateway hypothesis, young cannabis users should still be considered as a risk group for intervention programs. Other findings indicate that hard drug users are likely to be poly-drug users, and that interventions must address the use of multiple drugs instead of a single hard drug. Almost two-thirds of the poly drug users in the 2009–2010 Scottish Crime and Justice Survey used cannabis.
The gateway effect may appear due to social factors involved in using any illegal drug. Because of the illegal status of cannabis, its consumers are likely to find themselves in situations allowing them to acquaint with individuals using or selling other illegal drugs. Studies have shown that alcohol and tobacco may additionally be regarded as gateway drugs; however, a more parsimonious explanation could be that cannabis is simply more readily available (and at an earlier age) than illegal hard drugs. In turn, alcohol and tobacco are typically easier to obtain at an earlier age than is cannabis (though the reverse may be true in some areas), thus leading to the "gateway sequence" in those individuals, since they are most likely to experiment with any drug offered.
A related alternative to the gateway hypothesis is the common liability to addiction (CLA) theory. It states that some individuals are, for various reasons, willing to try multiple recreational substances. The "gateway" drugs are merely those that are (usually) available at an earlier age than the harder drugs. Researchers have noted in an extensive review that it is dangerous to present the sequence of events described in gateway "theory" in causative terms as this hinders both research and intervention.
In 2020, the National Institute on Drug Abuse released a study backing allegations that marijuana is a gateway to harder drugs, though not for the majority of marijuana users. The National Institute on Drug Abuse determined that marijuana use is "likely to precede use of other licit and illicit substances" and that "adults who reported marijuana use during the first wave of the survey were more likely than adults who did not use marijuana to develop an alcohol use disorder within 3 years; people who used marijuana and already had an alcohol use disorder at the outset were at greater risk of their alcohol use disorder worsening. Marijuana use is also linked to other substance use disorders including nicotine addiction." It also reported that "These findings are consistent with the idea of marijuana as a "gateway drug". However, the majority of people who use marijuana do not go on to use other, "harder" substances. Also, cross-sensitization is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances."
There are also other difficulties in researching the effects of cannabis. Many people who smoke cannabis also smoke tobacco. This causes confounding factors, where questions arise as to whether the tobacco, the cannabis, or both that have caused a cancer. Another difficulty researchers have is in recruiting people who smoke cannabis into studies. Because cannabis is an illegal drug in many countries, people may be reluctant to take part in research, and if they do agree to take part, they may not say how much cannabis they actually smoke.
Footnotes
Citations
Recreational
Spiritual
Consumption
Modes of consumption
Consumption by country
United States
Adverse effects
Short-term
Fatality
Long-term
Psychological effects
Neuroimaging
Cannabis dependence
Psychiatric
Physical
Emergency department visits
Reproductive health
Secondhand cannabis smoke
Pharmacology
Mechanism of action
Pharmacokinetics
Chemistry
Chemical composition
Detection in body fluids
Varieties and strains
Psychoactive ingredients
Laced cannabis and synthetic cannabinoids
Preparations
Marijuana
Kief
Hashish
Tincture
Hash oil
Infusions
Marihuana prensada
History
Ancient history
Modern history
Culture, legality and economics
Culture
Legality
Legal status by country
Economics
Production
Price
Cannabis as a gateway drug
Research
See also
Further reading
External links
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