[2] It has a history of cultivation originating in the Harar area (present day eastern Ethiopia) and subsequently introduced at different times to countries nearby in East Africa and Southern Arabia, most notably Yemen.

In the United States (US) and Turkey, the botanical specimen (plant) Catha edulis is not prohibited, but the consumption and distribution of harvested leaves or possession for recreational use is illegal.

By contrast, its production, sale, and consumption are all fully legal—or not mentioned in a legal context at all—in the nations where its use is culturally significant, including Djibouti, Ethiopia, Kenya, Somalia, Sudan, Uganda and Yemen.

[7][8] In Israel, which hosts a population of Yemenite Jews, only the consumption of the plant's leaves in its natural state is permitted; "khat extracts" are illegal, because they became a street drug and were popularly abused in the 2000s.

[10][11] The khat plant is known by a variety of names, such as qat and gat in Yemeni Arabic, qaat and jaad in Somali, and chat in Harari[12] and Amharic.

In the US, freshly-packed khat leaves are sold in the African and Middle Eastern markets of Boston, Dallas, Los Angeles, and New York City, where the demand is highest.

[21] Traditionally, khat is used as a socialising drug as in Yemen, where khat-chewing is predominantly a male habit combined with conversation, hookah smoking, and tea drinking.

[24] Water consumption is high and groundwater levels in the Sana'a basin are diminishing, so government officials have proposed relocating large portions of the population of the city to the Red Sea coastal areas.

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.

[45] Receptors for serotonin show a high affinity for cathinone, suggesting this chemical is responsible for feelings of euphoria associated with chewing khat.

[49] 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.

[54] 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.

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.

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.Nowadays khat consumption is limited to East Africa and South Western Arabia.

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),[6] although the WHO does not consider khat to be seriously addictive.

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.

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.

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.

[107] 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.

[110] 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.

[111] 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.

[114] 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.

[116] On 3 July 2013, the British Home Secretary Theresa May announced that khat was to be banned in Britain, designating it a Class C substance under the Misuse of Drugs Act 1971.

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."

[125] In January 2015, the Bristol Post reported that most khat houses in the city had closed down, "forcing users to take the drug in their homes instead".

The local police had initially not sought to enforce the ban, giving users a grace period, but according to the Bristol Post had recently started to take action against khat use and had issued three warnings and 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.

Channel 4 News reported in September 2014 that before the ban, 20 tonnes of khat arrived at Heathrow Airport daily, and it would sell for £3 per bundle.

[144] In South America, there is no legislation regarding khat; the active ingredients in the plant can be found in several weight control compounds sold in the continent.

[148] The inaugural event for the KRP was held in Sharm El-Sheik, Egypt, in December, 2009[149] in collaboration with the International Brain Research Organization (IBRO) and its local affiliates.