Aloe is a perennial plant native to Africa and naturalized in many arid regions of North and South America and Asia. The plant has fleshy, tapered leaves, which can reach up to 20 inches in length and usually grow in a rosette pattern. A flower stem, which may be up to three feet high, grows from the center of the plant, bearing long yellow flowers. The leaves have saw-like teeth along their edges and are filled with a clear gel. The gel and a yellow resin (or latex) from the leaves are used for health purposes.
Two portions of the aloe leaf are used, each with distinctly different chemical composition. The bitter yellow liquid, or latex, contains compounds known as anthraquinones, which include aloe-emodin, barboloin, aloin, and others. The inner gel contains plant sterols, saponins, salicylic acid, amino acids, vitamins, and minerals.
For use as a laxative, experts recommend aloe latex powders or liquid preparations providing the equivalent of 20 to 30 mg aloin per day. Reported side effects include gastrointestinal discomfort and cramps. Aloe latex should not be used by people with intestinal obstruction or inflamed intestinal diseases such as appendicitis or Crohn's disease. Long term use/abuse can cause potassium deficiency, which may lead to cardiovascular disorders. Aloe gel can be used liberally for topical applications.