Aloin is one of the element of the bitter juice of the aloe leaves. When the leaves are cut, the juice that flows out is usually collected and then treated to obtain aloins.

According to W. A. Shenstone, two classes of Aloins are to be recognized: (1) nataloins, which yield picric and oxalic acids with nitric acid, and do not give a red coloration with nitric acid; and (2) barbaloins, which yield aloetic acid (C₇H₂N₃O₅), chrysammic acid (C₇H₂N₂O₆), picric and oxalic acids with nitric acid, being reddened by the acid. This second group may be divided into a-barbaloins, obtained from Barbadoes aloes, and reddened in the cold, and b-barbaloins, obtained from Socotrine and Zanzibar aloes, reddened by ordinary nitric acid only when warmed or by fuming acid in the cold. Nataloin (2C₁₇H₁₃O₇·H₂O) forms bright yellow scales. Barbaloin (C₁₇H₁₈O₇) forms yellow prismatic crystals. Aloes also contain a trace of volatile oil, to which its odour is due.

Aloetrade America is proud to offer the best aloe bitter sap (aloe gum or aloe latex) and aloin, mostly from plantations in Venezuela, Mexico, Ecuador, South Africa, Tanzania, Lenya, India and China. Aloin products are processed in Mexico through a joint venture partner.