Aloe vera is our Herb of the Month for March.  It seemed appropriate, knowing that we're talking about herbal first aid this month.  Aloe is probably one of most familiar first aid plants here in the United States.  If you don't already have one growing on your kitchen window sill, you probably know someone who does or at least have heard that some people do that! 
     Also known as Aloe barbadensis, it is native to south and east Africa, but has flourished in many tropical and sub-tropical areas.  There are a number of different aloes, and many have similar therapeutic properties.  The African aloe is not, however, related to what are sometimes called American aloes - which are actually agaves and native to the American southwest.   Aloe has a long history of medicinal use, being noted in writings of the pre-Christian era, as well as by Pliny and Dioscorides in the first century.  It was known as the "plant of immortality" in ancient Egypt and was often presented as a burial gift to deceased Pharaohs.  Someone started a rumor that Cleopatra used it to maintain her beautiful skin.  I cannot verify that rumor, nor the claim that she had beautiful skin!  It was probably used in Great Britain by the 10th century and was regularly imported there by the early 17th century.
     Aloe has two very distinct actions as a medicine that come from two distinct parts of the plant.  It is important to understand these differences because they are NOT inter-changeable in use or in safety.
     The most commonly known use for aloe is as a skin soother and healer.  Aloe is a common ingredient in many cosmetic and medicinal skin preparations.  This is why it's so often found in the kitchen, as the fresh juice from its leaves is used on minor burns.    The clear, mucilaginous (gooey, slimy, viscuous) gel in the leaves contains a number of polysaccharides that have immune-modulating, anti-inflammatory, pain/itch-relieving and healing proprerties (acemannan or glucomannan is the primary healer polysaccharide identified thus far).  These same healing properties that we use topically (on our skin) for minor burns, sunburns, itches and eczema can also be applied internally.  Aloe vera juice is made from the gel of the leaf and has been used for ulcers and other inflammations of the digestive tract. 
     Aloe vera gel has also been studied and shown some success in the helping lower blood cholesterol and blood sugar.  Animal studies have shown activity as an anti-tumor agent and one study using acemannan in AIDS patients showed great promise in improving function and prognosis.   
     While any one individual may have an allergic reaction to any one specific plant, there is no toxicity associated with the use of aloe on the skin.  This is also true with use of the gel as juice for internal use. 
     The second use for aloe is as a laxative.  This preparation of aloe comes from a different part of the plant and must be used much more carefully.  At the base of the aloe leaf there is a yellow sap that contains a high level of a group of chemical compounds called anthraquinones that are responsible for its laxative action.  These compounds are activated by intestinal bacteria after ingestion, so the effects are not immediate but come on 10-14 hours after taking the aloe. 
     In 2002, the FDA limited the use of this preparation of aloe in over-the-counter products.  Adverse effects from the anthraquinones (barbaloin, sometimes listed simply as aloin, is a specific culprit) can be serious if not used appropriately.  Chronic use will deplete electrolytes, especially potassium, in the body which can cause problems with muscle weakness and cardiac rhythms.  Such use can also be addictive and cause problems with increased constipation when discontinued.  The use of any anthraquinones is CONTRAINDICATED in:
   **pregnancy and breastfeeding
   **with any medications or herbs that contain cardiac glycosides
   **ulcerative colitis and Crohn's disease
   **inflamed hemorrhoids and intestinal obstruction
   **other undiagnosed abdominal pain

So, I think you can see that you would not want to confuse the two preparations of aloe!  If you keep an aloe plant in your home, be comfortable in using the clear liquid goo that comes out of the leaf when you cut it on any minor skin irritation.  Avoid using the base of the leaf.  If you want to use the gel or juice for internal healing, commercial products made to be ingested have removed all the anthraquinones.  That said, all commercial products will not be the same in their healing abilities.  Processing of the aloe must be done carefully to maintain therapeutic levels of polysaccharides which are largely insoluble in alcohol - a common extractor in manufacturing.  They are also not very bioavailable to us, so starting out with high levels of polysaccharides in the original product is important for getting a therapeutic amount into our actual systems.  
     Aloe vera is a terrific plant you can enjoy having in your kitchen window and as part of your home first aid kit!