The purpose of this review is to evaluate what is currently known about the pharmacology of cathinone derivatives. Cathinone is the principal active constituent of khat responsible for the stimulant effects that have led khat to be known as a ‘natural amphetamine’. Synthetic derivatives have been abused for their amphetamine-like stimulant effects, most notably methylone, methcathinone (ephedrone), and 4-methlymethcathinone (mephedrone). To date, cathinone and methcathinone have been studied most, demonstrating amphetamine-like effects in a range of in vitro and in vivo investigations, albeit less potently than amphetamines. In humans, cathinone derivatives are usually administered orally, and in some cases by insufflation. Methcathinone has a longer history of abuse, being produced from readily available starting materials, and administered by injection. Mephedrone has become the best publicised cathinone derivative, amid considerable media and public concern about its legal status, its ready availability, and reports of serious toxicity and deaths following its use. As a consequence, there has been a clampdown on cathinone derivatives, dramatically changing their legal status in a number of countries. However, little objective evidence-based comparative experiments have been conducted to date between these compounds and their related amphetamines in order to make clear risk judgements. Such assessments have largely been predictive in nature, based on their structural similarity to amphetamines. It can be assumed that, despite their illegal status, cathinone-related compounds will continue to be prevalent drugs of abuse for the foreseeable future. Copyright © 2011 John Wiley & Sons, Ltd.