Khat is catha edulis, a flowering evergreen shrub. The leaves, twigs, and shoots are chewed fresh, or dried and made into tea or smoked. Khat leaves contain alkaloids called cathine and cathinone. The main responsible of the psychostimulants effects is cathinone, similar in pharmacological activity and structure to amphetamine but is 2-to-10 fold less active. Effects include euphoria, loss of appetite, reduction in fatigue, and increased heart rate. Cathinone stimulates the central nervous system by releasing dopamine, inhibiting dopamine and norephinefrine reuptake, and affecting serotonin system.
Usage of in East-Africa and the southwestern of the Arabia Peninsula, in countries such as Somalia, Kenya, Djibuti or Ethiopia, and is strongly associated with Yemen.