The khat plant contains psychoactive alkaloids with psychostimulant properties, and has been used for centuries as a recreational and religious drug, mainly in some African and Middle Eastern countries. With changing migration patterns, epidemiological and clinical outcomes may have changed. The aim of this article is to review current knowledge on pharmacological, epidemiological and clinical aspects of khat use. Khat use is still highly prevalent in the countries mentioned, and in African and Yemeni emigrant groups. Preclinical and clinical data confirm its addictive potential as well as possible psychological, psychiatric and medical consequences related to stimulant use; however, existing epidemiological studies do not focus on the prevalence of problematic use or dependence. There are no indications of high prevalence of khat use in other cultural and ethnic groups. Data are lacking on possible increased psychotogenic risks when khat is used outside of the original cultural context. As with alcohol use in many countries, khat use can be considered as a lifestyle in some specific countries, covering the spectrum from nonproblematic use to problematic use and dependence. Khat dependence is associated with high morbidity and societal and economical costs.