Catha edulis, universally known as khat, qat, chat, or abyssinian tea, is a slow-growing evergreen shrub or small tree belonging to the staff-vine or bittersweet family (Celastraceae). It is native to the Horn of Africa and the Arabian Peninsula, with deep historical roots in countries such as Ethiopia, Yemen, and Kenya. The genus name Catha is derived from an Arabic vernacular name for the plant (qat), while the species epithet edulis is Latin for "edible" or "eatable," highlighting its traditional consumption. Historically, khat has been cultivated and chewed for centuries across East Africa and the Middle East, serving a vital role in social rituals, religious ceremonies, and daily community gatherings where it acts as a mild stimulant.

The plant is a hardy evergreen that can survive in arid and semi-arid conditions where few other crops thrive, often growing as a shrub or reaching heights of up to 10 meters if left unharvested. It features smooth, greyish-green bark, elliptical, leathery leaves with finely toothed margins, and small clusters of white or yellowish flowers that yield three-valved capsule fruits. The most economically and culturally valuable parts of the plant are the tender young terminal shoots and leaves, which are harvested in the early morning hours to preserve their moisture and chemical potency. Catha edulis thrives in well-drained soils at higher altitudes, where cooler temperatures and intense sunlight encourage the biosynthesis of its active stimulant compounds.

As a food source and social masticatory, khat is unique because its primary use is not for culinary flavor or caloric nutrition, but rather for its psychoactive and stimulant properties. In traditional settings, fresh leaves and tender stems are methodically chewed for hours, forming a quid in the cheek that gradually releases the plant's juices. The taste is characteristically bitter, herbaceous, and astringent. In Yemen and parts of East Africa, communal chew sessions—often referred to as mahalraj or mkahwa—are deeply ingrained social customs that facilitate conversation, poetry recitation, and business negotiations. Because the active alkaloids degrade rapidly after harvest, fresh leaves must be wrapped in banana leaves or plastic bags and rushed to local markets daily.

Nutritionally and biochemically, Catha edulis is internationally renowned for its central nervous system stimulants, primarily cathinone and cathine (norpseudoephedrine). Cathinone is structurally and pharmacologically similar to amphetamine, acting as a potent dopamine reuptake inhibitor that produces alertness, euphoria, and increased energy, though it also suppresses appetite and delays sleep. Due to its high abuse potential and dependence liability, cathinone is classified as a controlled substance in many countries outside its native regions. In addition to these alkaloids, the plant contains significant amounts of Vitamin C, amino acids, and various astringent tannins, the latter of which contribute to its dry, bitter mouthfeel and are occasionally utilized in traditional folk medicine to soothe mild gastrointestinal upsets.