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Catha edulis (khat, qat) is a flowering plant native to the Horn of Africa and the Arabian Peninsula. Among communities from these areas, khat chewing has a history as a social custom dating back thousands of years.
Khat contains a monoamine alkaloid called cathinone, an amphetamine-like stimulant, which is said to cause excitement, loss of appetite and euphoria. In 1980, the World Health Organization (WHO) classified it as a drug of abuse that can produce mild-to-moderate psychological dependence (less than tobacco or alcohol), although WHO does not consider khat to be seriously addictive. The plant has been targeted by anti-drug organizations such as the DEA. It is a controlled substance in some countries, such as Canada, Germany, the United Kingdom, and the United States (de facto), while its production, sale, and consumption are legal in other nations, including Djibouti, Ethiopia, Somalia, and Yemen.
- 1 Nomenclature
- 2 Description
- 3 Cultivation and uses
- 4 Health effects
- 5 Chemistry and pharmacology
- 6 Demographics
- 7 History
- 8 Regulation
- 8.1 Africa
- 8.2 Asia
- 8.3 Europe
- 8.4 North America
- 8.5 Oceania
- 8.6 South America
- 9 Research programs
- 10 See also
- 11 Notes
- 12 References
- 13 Bibliography
- 14 External links
Khat goes by various traditional names, such as kat, qat, qaad, ghat, chat, tschat, Abessinischer Tee, Abyssinian Tea, Somali Tea, Arabian Tea, and Kafta in its endemic regions of the Horn of Africa and the Arabian Peninsula. In the African Great Lakes region, where Catha edulis is in some areas cultivated, it is known as miraa, muhulo and muirungi. In South Africa, the plant is known as Bushman's Tea. Other names for khat include Chat Tree and Flower of Paradise.
Khat is a slow-growing shrub or tree that typically attains a height of between 1 and 5 m (3.3 and 16.4 ft). However, it can reach heights of up to 10 metres (33 ft) in equatorial areas. The plant usually grows in arid environments, at a temperature range of 5 to 35 °C (41 to 95 °F). It has evergreen leaves, which are 5–10 cm long and 1–4 cm broad. The shrub's flowers are produced on short axillary cymes that are 4–8 cm in length. Each flower is small, with five white petals. The samara fruit is an oblong, three-valved capsule, which contains one to three seeds.
Cultivation and uses
The khat plant is known by a variety of names, such as qat and gat in Yemen, qaat and jaad in Somalia, and chat in Ethiopia. It is also known as jimma in the Oromo language. Khat has been grown for use as a stimulant for centuries in the Horn of Africa and the Arabian Peninsula. There, chewing khat predates the use of coffee and is used in a similar social context.
Although the practice of khat-chewing is still primarily restricted to its original area of cultivation in the Red Sea area, the khat plant has over the years found its way to Southern Africa as well as tropical areas, where it grows on rocky outcrops and in woodlands. The shrub is today scattered in the KwaZulu-Natal, Eastern Cape, Western Cape and Mpumalanga provinces of South Africa, in addition to Swaziland and Mozambique.
Its fresh leaves and tops are chewed or, less frequently, dried and consumed as tea, to achieve a state of euphoria and stimulation; it also has anorectic side effects. The leaves or the soft part of the stem can be chewed with either chewing gum or fried peanuts to make it easier to chew.
Khat use has traditionally been confined to the regions where it is grown, because only the fresh leaves have the desired stimulating effects. In recent years, however, improved roads, off-road motor vehicles, and air transportation have increased the global distribution of this perishable commodity, and as a result, the plant has been reported in England, Wales, Rome, Amsterdam, Canada, Israel, Australia, New Zealand, and the United States. Traditionally, khat is used as a socialising drug, and this is still very much the case in Yemen, where khat-chewing is predominantly a male habit. Yemenis use traditional costumes and chew the stimulating plant in the afternoons. Chewing khat is also part of the Yemeni business culture to promote decision-making, but foreigners are not expected to participate. Some Yemeni women have their own saloons for the occasion, and participate in chewing khat with their husbands on weekends.
Khat is so popular in Yemen, its cultivation consumes much of the country's agricultural resources. An estimated 40% of the country's water supply goes towards irrigating it, with production increasing by about 10% to 15% every year. One "daily bag" of khat requires an estimated 500 litres (130 US gal) of water to produce. Water consumption is so high, groundwater levels in the Sanaa basin are diminishing, so government officials have proposed relocating large portions of the population of Sana'a to the coast of the Red Sea.
One reason for khat being cultivated in Yemen so widely is the high income it provides for farmers. Some studies done in 2001 estimated that the income from cultivating khat was about 2.5 million Yemeni rials per hectare, while fruits brought only 0.57 million rials per hectare. Between 1970 and 2000, the area on which khat was cultivated was estimated to have grown from 8,000 to 103,000 hectares.
In other countries, outside of its core area of growth and consumption, khat is sometimes chewed at parties or social functions. It may also be used by farmers and labourers for reducing physical fatigue or hunger, and by drivers and students for improving attention. Within the counter-culture segments of the elite population in Kenya, khat (referred to locally as veve or miraa) is used to counter the effects of a hangover or binge drinking, similar to the use of the coca leaf in South America.
It takes seven to eight years for the khat plant to reach its full height. Other than access to sun and water, khat requires little maintenance. Ground water is often pumped from deep wells by diesel engines to irrigate the crops, or brought in by water trucks. The plants are watered heavily starting around a month before they are harvested to make the leaves and stems soft and moist. A good khat plant can be harvested four times a year, providing a year-long source of income for the farmer.
Khat consumption induces mild euphoria and excitement, similar to that conferred by strong coffee. Individuals become very talkative under the influence of the plant. The effects of oral administration of cathinone occur more rapidly than the effects of amphetamine pills; roughly 15 minutes as compared to 30 minutes in amphetamine. Khat can induce manic behaviours and hyperactivity, similar in effects to those produced by amphetamine.
The use of khat results in constipation. Dilated pupils (mydriasis) are prominent during khat consumption, reflecting the sympathomimetic effects of the drug, which are also reflected in increased heart rate and blood pressure.
Withdrawal symptoms that may follow occasional use include mild depression and irritability. Withdrawal symptoms that may follow prolonged khat use include lethargy, mild depression, nightmares, and slight tremor. Khat is an effective anorectic (causes loss of appetite). Long-term use can precipitate: negative impact on liver function, permanent tooth darkening (of a greenish tinge), susceptibility to ulcers, and diminished sex drive.
- infrequent hallucinations
- impaired inhibition (similar to alcohol)
- increased risk of myocardial infarction (heart attack)
- psychosis in extreme cases in the genetically predisposed
- oral cancer
Chemistry and pharmacology
The stimulant effect of the plant was originally attributed to "katin", cathine, a phenethylamine-type substance isolated from the plant. However, the attribution was disputed by reports showing the plant extracts from fresh leaves contained another substance more behaviourally active than cathine. In 1975, the related alkaloid cathinone was isolated, and its absolute configuration was established in 1978. Cathinone is not very stable and breaks down to produce cathine and norephedrine. These chemicals belong to the PPA (phenylpropanolamine) family, a subset of the phenethylamines related to amphetamines and the catecholamines epinephrine and norepinephrine. In fact, cathinone and cathine have a very similar molecular structure to amphetamine. Khat is sometimes confused with methcathinone (also known as cat), a Schedule I substance that possesses a similar chemical structure to the khat plant's cathinone active component. However, both the side effects and the addictive properties of methcathinone are much stronger than those associated with khat use.
When khat leaves dry, the more potent chemical, cathinone, decomposes within 48 hours, leaving behind the milder chemical, cathine. Thus, harvesters transport khat by packaging the leaves and stems in plastic bags or wrapping them in banana leaves to preserve their moisture and keep the cathinone potent. It is also common for them to sprinkle the plant with water frequently or use refrigeration during transportation.
When the khat leaves are chewed, cathine and cathinone are released and absorbed through the mucous membranes of the mouth as well as the lining of the stomach. The action of cathine and cathinone on the reuptake of epinephrine and norepinephrine has been demonstrated in lab animals, showing that one or both of these chemicals cause(s) the body to recycle these neurotransmitters more slowly, resulting in the wakefulness and insomnia associated with khat use.
Receptors for serotonin show a high affinity for cathinone, suggesting this chemical is responsible for feelings of euphoria associated with chewing khat. In mice, cathinone produces the same types of nervous pacing or repetitive scratching behaviours associated with amphetamines. The effects of cathinone peak after 15 to 30 minutes, with nearly 98% of the substance metabolised into norephedrine by the liver.
Cathine is somewhat less understood, being believed to act upon the adrenergic receptors causing the release of epinephrine and norepinephrine. It has a half-life of about three hours in humans. The medication bromocriptine can reduce cravings and withdrawal symptoms within 24 hours.
An estimated 10 million people globally use khat on a daily basis. It is grown principally by communities in the Horn of Africa and the Arabian peninsula, where khat-chewing has a long history as a social custom dating back thousands of years.
The traditional form of khat chewing in Yemen involves only male users; khat chewing by females is less formal and less frequent. Researchers estimate about 70–80% of Yemenis between 16 and 50 years old chew khat, at least on occasion. Yemenis spend an estimated 14.6 million person-hours per day chewing khat. Researchers have also estimated that families spend about 17% of their income on khat.
According to some sources, khat was first grown in Ethiopia, with the explorer Sir Richard Burton suggesting the plant was later introduced to Yemen from Ethiopia in the 15th century. He specifically mentions the eastern city of Harar as the birthplace of the plant.
However, amongst communities in the Horn of Africa (Djibouti, Eritrea, Ethiopia, Somalia) and the Arabian Peninsula, khat-chewing has a long history as a social custom dating back thousands of years.
The Ancient Egyptians considered the khat plant a divine food, which was capable of releasing humanity's divinity. The Egyptians used the plant for more than its stimulating effects; they used it for transcending into "apotheosis", with the intent of making the user god-like. Sufis also used it to intensify their mystical experience and to facilitate a sense of union with God.
The earliest known documented description of khat is found in the Kitab al-Saidala fi al-Tibb كتاب الصيدلة في الطب, an 11th-century work on pharmacy and materia medica written by Abū Rayhān al-Bīrūnī, a Persian scientist and biologist. Unaware of its origins, al-Bīrūnī wrote that khat is:
[A] commodity from Turkestan. It is sour to taste and slenderly made in the manner of batan-alu. But khat is reddish with a slight blackish tinge. It is believed that batan-alu is red, coolant, relieves biliousness, and is a refrigerant for the stomach and the liver.
You observed a new peculiarity in this city – everyone chewed leaves as goats chew the cud. There is a type of leaf, rather wide and about two fingers in length, which is widely sold, as people would consume these leaves just as they are; unlike betel leaves, which need certain condiments to go with them, these leaves were just stuffed fully into the mouth and munched. Thus when people gathered around, the remnants from these leaves would pile up in front of them. When they spat, their saliva was green. I then queried them on this matter: ‘What benefits are there to be gained from eating these leaves?’ To which they replied, ‘None whatsoever, it’s just another expense for us as we’ve grown accustomed to it’. Those who consume these leaves have to eat lots of ghee and honey, for they would fall ill otherwise. The leaves are known as Kad."
And one may sleep well if, during the day, too much kat has not been chewed. The leaves of the drug called kat are the chief source of pleasurable excitement in these districts of East Africa. Botanists, taking the native name for the plant, turn it into Catha edulis, eatable kat. It is much used by the Arabs, to whom it is sent in camel loads, consisting of a number of small parcels, each containing about forty slender twigs, with the leaves attached, carefully, wrapped so as to avoid exposure to the air. These leaves are chewed, and act upon the spirits of those using them, much as a strong dose of green tea acts upon us in Europe, when it acts agreeably. Europeans used to stronger stimulants, are little affected by the use of kat, but among the more temperate Arabs it is so welcome a provocative to good humour, that about two hundred and eighty camel-loads of it are used every year in Aden only.
In 1965, the World Health Organization (WHO) Expert Committee on Dependence-producing Drugs' Fourteenth Report noted, "The Committee was pleased to note the resolution of the Economic and Social Council with respect to khat, confirming the view that the abuse of this substance is a regional problem and may best be controlled at that level." For this reason, khat was not scheduled under the Single Convention on Narcotic Drugs. In 1980, the WHO classified the plant as a drug of abuse that can produce mild to moderate psychological dependence (less than tobacco or alcohol), although the WHO does not consider khat to be seriously addictive. It is a controlled or illegal substance in some countries, but is legal for sale and production in others.
Khat is legal in Ethiopia.
Khat is legal in Somalia.
Khat is legal in Djibouti.
Khat is legal in Kenya. However, two of its active components, cathinone and cathine, are classed as Class C substances.
In South Africa, Catha edulis is a protected tree.
Khat is consumed mainly by Yemenite Jews. The raw plant is also available for sale in several open markets. A cocktail of Arak and minced frozen khat, mixed with grapefruit juice, has become popular in the south of the country in recent years. However, as of June 2012, the Israeli anti-drug authority announced that beverages containing Khat are considered illegal as per the dangerous drug ordinance of the state of Israel nrg. In 2003, Hagigat, a pill based on extracted cathinone, began to be sold in kiosks in Israel. Following several cases of hospitalisation, the Israeli Ministry of Health classified cathinone as a dangerous drug, and Hagigat was outlawed. The plant itself is allowed to be chewed and sold, as no harm was found in normal quantities. Etrogat is a popular juice from Jerusalem sold by Uzi-Eli Hezi and also many variations of Khat juice can be found across Israel.
Khat is illegal in Malaysia.
Khat is illegal in Saudi Arabia.
Khat is legal in Yemen. However, cultivation of the crop and the selling of its leaves are governed by a series of regulations. In 2007, the Yemeni government passed a law that restricted the cultivation of khat in a number of agricultural flatlands and basins with high water stress. The Law Concerning the General Sales Tax in 2005 also set the tax rate on khat at 20% of its retail price.
Khat has been illegal in Denmark since 1993.
Khat is classified as an illegal drug in Finland, and possession, use and sale of the substance is prohibited and punishable. As with all illegal drugs, operating a motor vehicle with detectable levels of Khat or its metabolites in one's system can also lead to a conviction for driving under the influence, even if the driver does not appear intoxicated.
Khat is prohibited in France as a stimulant.
In Germany, cathinone is listed as a "non-trafficable substance", which makes the possession, sale and purchase of fresh khat illegal. The derivative cathine is only available on prescription, while norephedrine is not listed.
In August 2010 the Icelandic police intercepted khat smuggling for the first time. 37 kg were confiscated. The drugs were most likely intended for sale in Canada. Again in May 2011 the police intercepted around 60 kg.
Khat is a controlled drug for the purpose of the Misuse of Drugs Act 1977 and Schedule 1 of the Misuse of Drugs Regulations 1988. As such its unauthorised possession and supply is prohibited.
In the Netherlands, the active ingredients of khat, cathine and cathinone, are qualified as hard drugs and forbidden. Use is mostly limited to the Somali community. In 2008 health minister Ab Klink decided against qualifying the unprocessed plant as drugs after consultation with experts. However, on 9 January 2012 the Dutch government announced a ban on khat.
Norwegian Customs seized 10 metric tons of khat in 2010, an increase from less than 4 in 2006.
In Poland, khat is classified as a narcotic drug, and is illegal to use, sell and possess.
The drug was prohibited in Sweden in 1989, without research. 
In Switzerland, khat is illegal. It is classified as a narcotic drug.
Khat was made illegal in the UK on 24 June 2014. Concerns had been expressed by commentators, health professionals and community members about the use of khat in the UK, particularly by immigrants from Somalia, Yemen and Ethiopia. Studies of the effects of khat use by immigrants on their mental health suggested that there was a need for better research on khat-chewing and its possible link with psychiatric disorders; it also suggested that public discourse on the issue displayed elements of a moral panic. Some Somali community organisations also campaigned for khat to be banned. As a result of these concerns, the Home Office commissioned successive research studies to look into the matter, and in 2005, presented the question of khat's legal status before the Advisory Council on the Misuse of Drugs. The study concluded that most of the participants who were using khat were using it moderately in terms of both the quantity used and the frequency and duration of chewing sessions, and that khat use was typically a social activity. Only a small minority of the study participants' khat use was judged to be excessive. After a careful review of the evidence, the Advisory Council on the Misuse of Drugs recommended in January 2006 that the status of khat as a legal substance should remain for the time being.
In 2008, Conservative politician Sayeeda Warsi stated that a future Conservative government would ban khat. The website of the Conservative Party, which in 2010 became the larger party in a UK coalition government, previously stated that a Conservative government would "Tackle unacceptable cultural practices by", amongst other measures, "classifying Khat". In 2009, the Home Office commissioned two new studies in the effects of khat use and in June 2010, a Home Office spokesperson stated: "The Government is committed to addressing any form of substance misuse and will keep the issue of khat use under close scrutiny".
During a parliamentary debate on the legality issue on 11 January 2012, Mark Lancaster, the Conservative Member of Parliament for Milton Keynes, stated that the importation of Khat into the UK stands at 10 tonnes every week.
On 23 January 2013, the Advisory Council on the Misuse of Drugs (ACMD) said there was "insufficient evidence" that khat caused health problems. The ACMD said there was "no evidence" khat was directly linked with serious or organised crime, and was chewed to obtain a "mild stimulant effect much less potent than stimulant drugs, such as amphetamine".
Alex Miller, a journalist from the Montreal, Canada-based magazine and television channel Vice, looked into the use of the substance and the potential impact of the ban for BBC nightly current affairs programme Newsnight and for a Vice documentary.
Kenyan MPs appealed to the UK not to "condemn people" by banning the herbal stimulant khat
In March 2014, the United Kingdom House of Commons' Home Affairs Select Committee announced that it would continue to lobby for the UK government not to go through with its intended ban on khat. The committee had shortly before also completed an inquiry and a report recommending that the British authorities refrain from banning the plant.
On 12 May 2014, the House of Lords passed a Motion to Approve the Misuse of Drugs Act 1971 (Designation)(Amendment) (No. 2)(England, Wales and Scotland) Order 2014, in order to control Catha edulis as a Class C drug. An amendment was proposed stating that, "this House regrets that Her Majesty’s Government’s plans for the introduction of the Order do not include provisions for a 12-month review of the impact of the reclassification of khat in view of the highly unusual community focus of its use, for putting a detailed policing strategy in place before a ban takes effect, or for a health strategy to prevent a transfer of addiction to other substances; and do not commit the Department for International Development to do more work with the government of Kenya to alleviate the effect of the reclassification on the Kenyan economy." However, the amendment was defeated by vote. The prohibition came into effect on 24 June 2014.
By January 2015, most khat houses in the UK had closed down operations, and the shops that used to sell the plant stopped doing so. While a few chewers anecdotally asserted that some sellers still offered khat underground, there was only one major seizure since the prohibition, in the Bristol county of Easton in September 2014. Some khat bags were also confiscated in January, but no arrests were made in connection with the seizure. In January 2015, the Avon and Somerset Police reported that it only had to give three people warnings for possession and one person a caution. Additionally, the Somali Resource Centre indicated that the ban seemed to have been effective, and that the prohibition had all but destroyed the import market since the plant has to be fresh in order to be consumed.
In Canada, khat is a controlled substance under Schedule IV of the Controlled Drugs and Substances Act (CDSA), meaning it is illegal to seek or obtain unless approved by a medical practitioner. Punishment for the possession of khat could lead to a maximum sentence of three years in prison. The maximum punishment for trafficking or possession with the intent of trafficking is ten years in prison.
In 2008, Canadian authorities reported that khat is the most common illegal drug being smuggled at airports.
However, in 2012 the Ontario Court of Appeal upheld a 2011 absolute discharge of a young woman who brought 34 kilograms of khat into Canada in 2009. According to the defence, the ruling recognises that there is no empirical evidence that khat is harmful.
In the United States, cathinone is a Schedule I drug, according to the US Controlled Substance Act. The 1993 DEA rule placing cathinone in Schedule I noted that it was effectively also banning khat:
Cathinone is the major psychoactive component of the plant Catha edulis (khat). The young leaves of khat are chewed for a stimulant effect. Enactment of this rule results in the placement of any material that contains cathinone into Schedule I.
Catha edulis (khat) is a stimulant narcotic that is similar to that of amphetamine and its congeners, not a drug as categorised by US FDA (United States Food & Drug Administration) and FDA import Alert #66-23 (published date 03/18/2011) states that "Districts may detain, without physical examination, all entries of khat", based on section 801(a) (3) of the Federal Food, Drug, and Cosmetic Act on the grounds that "its labeling fails to bear adequate directions for use."
Khat has been seized by local police and federal authorities on several occasions.
The plant itself is specifically banned in Missouri:
Khat, to include all parts of the plant presently classified botanically as catha edulis, whether growing or not; the seeds thereof; any extract from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of the plant, its seed or extracts.
In Australia, the importation of khat is controlled under the Customs (Prohibited Imports) Regulations 1956. Individual users must obtain permits from the Australian Quarantine and Inspection Service and the Therapeutic Goods Administration to import up to 5 kg per month for personal use. Permits must also be endorsed by the Australian Customs Service which regulates the actual import of the drug. In 2003, the total number of khat annual permits was 294 and the total number of individual khat permits was 202.
In New Zealand, khat is listed as a Class C drug, in the same category as cannabis and codeine.
In South America, there is no legislation regarding khat; the active ingredients in the plant can be found in several weight control compounds sold on the continent.
In 2009, the University of Minnesota launched the Khat Research Program (KRP), a multidisciplinary research and training program focusing on the neurobehavioral and health effects of khat, led by Prof. Dr. Mustafa al'Absi. The program was funded by the National Institutes of Health and the National Institute for Drug Abuse of the United States. The inaugural event for the KRP was held in Sharm El-Sheik, Egypt, in December, 2009 in collaboration with the International Brain Research Organization (IBRO) and its local affiliates.
- Betel leaves, a related narcotic herb in Southeast Asia
- List of Southern African indigenous trees
- either from impaired insight into symptoms by the khat chewer, delay to care, or poorly understood pathophysiological mechanisms
- Dickens, Charles (1856) [Digitized February 19, 2010]. "The Orsons of East Africa". Household Words: A Weekly Journal, Volume 14. Bradbury & Evans. p. 176. Retrieved 9 January 2014. (Free eBook)
- Al-Mugahed, Leen (2008). "Khat Chewing in Yemen: Turning over a New Leaf: Khat Chewing Is on the Rise in Yemen, Raising Concerns about the Health and Social Consequences". Bulletin of the World Health Organization 86 (10): 741–2. doi:10.2471/BLT.08.011008. PMC 2649518. PMID 18949206. Retrieved 9 January 2014.
- Nutt, D.; King, L.A.; Saulsbury, C.; Blakemore, Colin (March 2007). "Development of a rational scale to assess the harm of drugs of potential misuse". Lancet 369 (9566): 1047–53. doi:10.1016/S0140-6736(07)60464-4. PMID 17382831.
- DEA. "2006 in Pictures". Archived from the original on 1 December 2009.
- "Haight-Ashbury Free Medical Clinic". Journal of psychoactive drugs (Haight-Ashbury Publications) 41: 3. 2009.
- "Khat facts". ADF. Retrieved 14 May 2013.
- "Growing Catha edulis". Plot55. Retrieved 26 January 2014.
- "USDA GRIN Taxonomy". Agricultural Research Service (US Department of Agriculture). Germplasm Resources Information Network.
- Rätsch, Christian (2004). The Encyclopedia of Psychoactive Plants: Ethnopharmacology and Its Applications. Park Street Press, U.S. ISBN 978-0892819782.
- "Protected Trees". Department of Water Affairs and Forestry, Republic of South Africa. 3 May 2013.
- "Catha edulis". Plantzafrica. Retrieved 15 January 2014.
- Simon, O'Rourke (13 December 2006). "Concerns over African methamphetamine-like drug in Hamilton". The New Zealand Herald. Retrieved 12 October 2011.
- Kirby, Alex (7 April 2007). "Yemen's khat habit soaks up water". BBC News. Retrieved 26 January 2014.
- Marshall, Tim (15 January 2010). "Sky News report on Yemen's Qat". Sky News. Retrieved 4 April 2010.
- Filkins, Dexter (11 April 2011). "After the Uprising". The New Yorker. Retrieved 5 April 2011.
- The Encyclopedia of Yemen (in Arabic) (2nd ed.). Alafif Cultural Foundation. 2003. pp. 2309–2314.[full citation needed]
- Nutt, D.; King, L. A.; Saulsbury, W.; Blakemore, C. (2007). "Development of a rational scale to assess the harm of drugs of potential misuse". The Lancet 369 (9566): 1047–1053. doi:10.1016/S0140-6736(07)60464-4. PMID 17382831.
- Peter, Kalix. (1983), "The Pharmacology of Khat and of the Khat Alkaloid Cathinone", in Randrianame, M.; Szendrei, K.; Tongue, A., The Health and Socioeconomic Aspects of Khat Use, Lausanne, Switzerland: Intl. Council on Drug and Addictions, pp. 140–143
- Drugs.com (1 January 2007). "Complete Khat Info".
- Giannini, A.J.; Castellani, S. (July 1982). "A manic-like psychosis due to khat (Catha edulis Forsk.)". Journal of Toxicology. Clinical Toxicology 19 (5): 455–9. doi:10.3109/15563658208992500. PMID 7175990.
- "Long-term effects of chronic khat use: impaired inhibitory control". Frontiers in cognition. 12 January 2011. Retrieved 17 January 2011.
- Al-Motarreb, A. L.; Broadley, K. J. (October–December 2003). "Coronary and aortic vasoconstriction by cathinone, the active constituent of khat". Autonomic & Autacoid Pharmacology 23 (5–6): 319–26. doi:10.1111/j.1474-8673.2004.00303.x.
- "Khat - DrugInfo Clearinghouse". Druginfo.adf.org.au. 20 September 2006. Retrieved 28 July 2010.
- Hassan, Nageeb; Gunaid, Abdullah; Murray-Lyon, Iain. "British-Yemeni Society: The impact of khat-chewing on health: a re-evaluation". Al-bab.com. Retrieved 28 July 2010.
- Mateen, F. J.; Cascino, G. D. (November 2010). "Khat Chewing: A smokeless gun?". Mayo Clinic Proceedings 85 (11): 971–3. doi:10.4065/mcp.2010.0658. PMC 2966359. PMID 21037041.
- Cox, G. (2003). "Adverse effects of khat: a review". Advances in Psychiatric Treatment 9 (6): 456–63. doi:10.1192/apt.9.6.456.
- "DF - Khat". Drugfree.org. Retrieved 26 January 2014.
- Ahmed, M.B.; El-Qirbi, A.B. (August 1993). "Biochemical effects of Catha edulis, cathine and cathinone on adrenocortical functions". J Ethnopharmacol 39 (3): 213–6. doi:10.1016/0378-8741(93)90039-8. PMID 7903110.
- "Behavioral Effects of Cathinone".[dead link]
- Adeoya-Osiguwa, S.A.; Fraser, L.R. (March 2007). "Cathine, an amphetamine-related compound, acts on mammalian spermatozoa via beta1- and alpha2A-adrenergic receptors in a capacitation state-dependent manner". Hum. Reprod. 22 (3): 756–65. doi:10.1093/humrep/del454. PMID 17158213.
- Giannini, A. J.; Miller, N. S.; Turner, C. E. (1992). "Treatment of khat addiction". J Subst Abuse Treat 9 (4): 379–82. doi:10.1016/0740-5472(92)90034-L. PMID 1362228.
- Chevalier, A. (1949). "Les Cat's d'Arabie, d'Abyssinie et d'Afrique orientale". Revue de Botanique appliquée 29: 413.
- Burton, Richard (1856). First Footsteps in East Africa. ISBN 1-4191-1982-6.[page needed]
- Libermn, Mark (2003). "LANGUAGE RELATIONSHIPS: FAMILIES, GRAFTS, PRISONS". Basic Reference (Pittsburgh, PA: University Pennsylvania Academics) 28: 217–229. Retrieved 27 April 2012.
- Giannini, A.J.; Burge, H.; Shaheen, J.M.; Price, W.A. (1986). "Khat: another drug of abuse?". Journal of Psychoactive Drugs 18 (2): 155–8. PMID 3734955.
- The Green Leaf: Khat World Journal of Medical Sciences 7 (4): 210-223, 2012.
- Khat in the Western Indian Ocean - Regional Linkages and Disjunctures Neil Carrier et Lisa Gezon, 42-43 | 2009 : Plantes et Sociétés, p. 271-297.
- Kiple, Kenneth F.; Ornelas, Kriemhild Coneè (2001). The Cambridge World History of Food. Cambridge University Press. pp. 672–3. ISBN 0-521-40216-6. OCLC 174647831.
- Ché-Ross, Raimy (2000). "Munshi Abdullah's voyage to Mecca: A preliminary introduction and annotated translation". Indonesia and the Malay World 28 (81): 173–213. doi:10.1080/713672763.
- "World Health Organization Expert Committee on Dependence-producing Drugs: Fourteenth Report". United Nations Office of Drugs and Crime. Archived from the original on 3 August 2003.
- Thomson Gale (Firm), Countries of the World and Their Leaders Yearbook 2007, Volume 1, (Thomson Gale: 2006), p.545.
- "SAPTA - Khat". Archived from the original on 18 July 2012.
- "Visitors Please Do Not Carry Khat into China". May 4, 2014.
- Urquhart, Conal (4 September 2004). "Drugs and dance as Israelis blot out intifada". The Guardian.
- Bentur, Y.; Bloom-Krasik, A.; Raikhlin-Eisenkraft, B. (2008). "Illicit cathinone ("Hagigat") poisoning". Clinical toxicology (Philadelphia, Pa.) 46 (3): 206–210. doi:10.1080/15563650701517574. PMID 17852166.
- Doward, Jamie; Shah, Oliver (26 April 2009). "There are many drugs that help people get out of their minds yet stay within the law - they're called 'legal highs'". The Guardian (The Observer).
- "Khat (catha edulis)". Ekhat. Retrieved 29 June 2013.
- Gatter, Peer (2012). Politics of Qat - The Role of a Drug in Ruling Yemen. Ludwig Reichert Verlag, Wiesbaden. pp. 260, 335–336. ISBN 978-3-89500-910-5.
- Heffez, Adam (July 23, 2013). "How Yemen Chewed Itself Dry". Foreign Affairs. Retrieved 29 July 2013.
- "Khat:Social harms and legislation". Retrieved 26 March 2015.
- "Khat use on the increase in Finland". HELSINGIN SANOMAT. Retrieved 23 May 2011.
- "Hald lagt á fíkniefnið Khat í fyrsta sinn" (in Icelandic). 2010-08-19.
- "60 kíló af fíkniefnum" (in Icelandic). 2011-05-18.
- "khat" (in Dutch). Infopolitie.nl. Retrieved 2 April 2010.
- "Qat niet verboden" (in Dutch). DePers.nl. Retrieved 2 April 2010.
- "Kabinet verbiedt qat" (in Dutch). Nu.nl. 10 January 2012. Retrieved 10 January 2012.
- "NOVA paper 1/06". 16 March 2007.
- "Official statistics from the Norwegian Customs and Excise Authorities" (in Norwegian). 1 June 2011. Archived from the original on 19 July 2011.
- "Dz.U. 2009 nr 63 poz. 520".[dead link]
- "Loi fédérale sur les stupéfiants et les substances psychotropes" (in French).
- "The Misuse of Drugs (Designation) (Amendment) (No. 2) (England, Wales and Scotland) Order 2014". legislation.gov.uk. Retrieved 28 June 2014.
- Klein, Axel (2007). "Khat and the creation of tradition in the Somali diaspora". In Fountain, Jane; Korf, Dirk J. Drugs in Society: European Perspectives. Oxford: Radcliffe Publishing. pp. 51–61. ISBN 978-1-84619-093-3.
- Warfa, N.; Klein, A.; Bhui, K.; Leavey, G.; Craig, T.; Alfred Stansfeld, S. (2007). "Khat use and mental illness: A critical review". Social Science & Medicine 65 (2): 309–318. doi:10.1016/j.socscimed.2007.04.038. PMID 17544193.
- Jones, Aidan (8 May 2009). "More Somali migrants say Britain should ban khat". Christian Science Monitor. Retrieved 7 August 2010.
- Patel, Shilpa L.; Wright, Sam; Gammampila, Alex (2005). "Khat use among Somalis in four English cities". Online Report 47/05. Home Office. Retrieved 7 August 2010.
- Warsi, Sayeeda (15 June 2008). "Conservatives will ban khat". Comment is free (London: The Guardian). Retrieved 21 August 2010.
- "Where we stand: Community relations". Conservatives.com. Conservative Party. Archived from the original on 30 September 2008. Retrieved 21 August 2010.
- "Call for new controls on legal drug khat". Sky News. 19 June 2010. Archived from the original on 26 January 2014. Retrieved 26 January 2014.
- "Hansard 11 Jan 2012". Hansard. 11 January 2012. Retrieved 12 January 2012.
- "Khat: A review of its potential harms to the individual and communities in the UK". Advisory Council on the Misuse of Drugs. 23 January 2013.
- "Written statement to Parliament: Khat". HM Government. 3 July 2013.
- "Herbal stimulant khat to be banned". BBC News. 3 July 2013.
- "BBC News - Khat: What impact will UK herb stimulant ban have?". BBC News. Retrieved 24 January 2014.
- "YouTube - Khat Power: The Latest War On Drugs". Youtube.com. Retrieved 24 January 2014.
- "BBC News - Kenya appeals to UK not to ban khat". bbc.co.uk. Retrieved 3 April 2014.
- "UK legislators to press for lifting ban on Miraa Read". Standard Digital. 7 March 2014. Retrieved 17 March 2014.
- Text of Order
- "Misuse of Drugs Act 1971 (Amendment) (No. 2) Order 2014 — Motion to Approve: 12 May 2014: House of Lords debates - TheyWorkForYou". theyworkforyou.com. Retrieved 31 May 2014.
- "Denied: Kenya won't be allowed to sell khat in the UK". The Citizen. 13 June 2014. Retrieved 21 June 2014.
- "Khat in Bristol: Banned drug's still here – it's just moved underground". Bristol Post. 10 January 2015. Retrieved 20 February 2015.
- "Controlled Drugs and Substances Act". Laws.justice.gc.ca. 29 March 2010. Retrieved 4 April 2010.[dead link]
- "Gangs infiltrate Canada's airports". The Christian Science Monitor. 16 December 2008. Retrieved 2 April 2010.
- Powell, Betsy (20 April 2012). "Woman who brought khat to Canada wins appeal". The Star. Archived from the original on 9 January 2014. Retrieved 26 January 2014.
- "Erowid Khat Vault : Law : Federal Register vol 58, no 9". Erowid.org. Retrieved 2 April 2010.
- "Import Alert 66-23" (Press release). Food and Drug Administration. 2011-03-18. Retrieved 26 January 2014.
- Federal Register (14 January 1993). "Schedules of Controlled Substances: Placement of Cathinone and 2,5-Dimethoxy-4-ethylamphetamine Into Schedule I". Retrieved 1 February 2010.[clarification needed (citation makes no sense)]
- "Section 195-017 Substances, how placed in schedules-li". Moga.mo.gov. 28 August 2009. Retrieved 2 April 2010.
- Stewart, Cameron (23 July 2008). "Somali women demand government action on legal drug". The Australian. Retrieved 5 August 2008.
- "Guidance for completing Licence and Import Permit applications (Khat)". Department of Health and Ageing, Commonwealth of Australia. May 2008. Retrieved 5 August 2008.
- "Austlii Consolidated Acts – DRUGS MISUSE REGULATION 1987(Qld) – SCHEDULE 2". Austlii.edu.au. Retrieved 4 April 2010.
- "Associate Professor Heather Douglas, University of Queensland". Law.uq.edu.au. 9 December 2009. Retrieved 4 April 2010.
- "Misuse of Drugs Act 1975 No 116". legislation.govt.nz. July 2014. Retrieved 17 March 2015.
- "al'Absi Launches the Khat Research Program" (Press release). Med.umn.edu. Archived from the original on 8 December 2009. Retrieved 4 April 2010.
- "KRP". Khatresearch.org. Retrieved 4 April 2010.
- "KRP Symposium".[dead link]
- Gatter, Peer (2012). Politics of Qat: The Role of a Drug in Ruling Yemen. Ludwig Reichert Verlag, Wiesbaden, 862 pp. ISBN 978-3-89500-910-5. Link to the table of contents and to selected chapters.
- Hilton-Taylor (1998). Catha edulis. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006.
- Sahal Abdulle (2 January 2007). "Somali Islamists are gone – so 'khat' is back!". Reuters (Mogadishu). Retrieved 26 January 2014.
- Pendell, Dale (2002). Pharmakodynamis: Stimulating Plants, Potions and Herbcraft: Excitantia and Empathogenica. San Francisco: Mercury House.