The genus Aloe (Asphodelaceae), with nearly 420 species confined mainly to Africa, has over the years proved to be one of the most important sources of biologically active compounds. Over 130 compounds belonging to different classes including anthrones, chromones, pyrones, coumarins, alkaloids, glycoproteins, naphthalenes and flavonoids have so far been reported from the genus. Although many of the reports on Aloe are dominated by A. vera and A. ferox, there have also been a number of fruitful phytochemical studies on many other members of the genus. In this review an attempt is made to present all compounds isolated to date from Aloe. The biogenesis and chemotaxonomic significance of these compounds are also discussed.