Comparative TLC analysis of the root extracts of 32 Aloe species showed that chrysophanol, asphodelin, chrysophanol-8-methyl ether, aloechrysone, helminthosporin, aloesaponol III, aloesaponarin I, aloesaponol I, aloesaponarin II, aloesaponol II and laccaic acid D-methyl ester are widely distributed in these plants. Isoeleutherol, which is reported here for the first time as a natural product, occurs only in the Saponoriae series of Aloe. The chemotaxonomic implication of the distribution of these compounds for the genus Aloe is discussed.