Different aloes are associated with different macroscopical features depending on the species and the method of preparation. While cape aloes occurs as dark brown or greenish brown, glassy masses, curacao varies in colour from yellowish brown to chocolate brown. Sacotrine and Zanzibar aloes no longer official are of infrequent occurrence in commerce and they are more opaque and break with porous fracture.

Aloes contain a number of anthraquinone glycosides (10%–30%), principal of which are aloin A and B. They are c-glycosides and the active constituents vary qualitatively and quantitatively according to the species from which they are obtained. Aloesin, aloe resin A and C, aloenin B are resins isolated from aloe species.

The aloe vera gel on the other hand is largely composed of a mucilaginous polysaccharide consisting of glucomannans (acemannans), lectins, sterols, enzymes, pectic substances together with a range of other organic and inorganic compounds.