Aloe gel is perhaps the most widely recognized herbal remedy in the United States today, used to relieve thermal burn and sunburn, promote wound healing, and moisturize and soften skin. Everyone who uses it seems convinced that it works, and its millennia of use for the same conditions support that assumption. In addition, recent research suggests that aloe gel can help stimulate the body's immune system. However, the way aloe works is not yet fully understood.

Background
In the mid-1930s, researchers enthusiastically reported quick and complete healing of skin burns caused by X-rays and ultraviolet and gamma rays. The public became aware of their findings in Gertrude B. Foster's classic, Herbs for Every Garden (Dutton, 1966). Foster also noted that aloe was grown as a landscape plant in the tropics and as a houseplant in temperate climates. Although commercial development of aloe vera was already under way, its popularity exploded in the 1970s.

Two products in current use are derived from aloe leaves. The clear gel that forms naturally in the hollow interior of the leaf is the familiar product used to relieve burns and wounds, whereas specialized resin canal cells in the thick leaf epidermis produce a bitter yellow juice that is the source of the laxative drug aloe. Although they share certain components, these two products are distinctly different and should not be confused.

Aloe gel
The conventional pharmaceutical approach to the question "How does it work?" is to determine which individual chemical component of a plant is contributing to its healing activity. This opens the door to commercial extraction and refinement--processes that can be patented. In regard to aloe, however, investigation hasn't yet provided clear-cut answers. The gel comprises more than seventy-five compounds, including polysaccharides (complex carbohydrates), steroids, organic acids, enzymes, antibiotic agents, amino acids, and minerals. One enzyme found in aloe gel has been suggested as the primary component responsible for the gel's ability to heal burns.

Since the first clinical trials of the gel in the mid-1930s, subsequent trials have produced similar, positive results. However, evidence from those experiments and from many favorable case histories is inconclusive because much of the work suffered from poor experimental design and small test samples. Although recent, more thorough research has confirmed the likelihood of useful physiological effects, the gel's properties still haven't been ascribed to specific components. Among some of the recent findings: