Paging Dr. Frischer: Aloe vera

Throughout my childhood, an aloe plant grew in my backyard. I distinctly remember the large, thick, pointed green leaves and the clear substance that oozed out. If I had a cut or abrasion, I was told to rub the liquid onto my wound. Was this good advice?

Aloe vera has been commonly used for medicinal purposes throughout the ages. Ancient Egyptian writings mention the nourishing juice of the aloe vera plant. The list of historical figures who used aloe vera for various reasons purportedly includes Cleopatra, Alexander the Great, and Christopher Columbus.

The aloe vera plant is also known as burn plant, lily of the desert, and elephant’s gall. Aloe gel is found in the inner part of the leaf, and contains vitamins, minerals, amino acids and antioxidants. Aloe latex is yellow, and comes from just under the plant's skin. Some aloe products are made from the whole crushed leaf, and contain both gel and latex.

Aloe vera has a significant presence in the cosmetic, pharmaceutical and food industries, with an estimated annual market value of $13 billion worldwide. It’s claimed benefits range from youth and beauty to digestion and health.

But what benefits are supported by scientific studies? There is good evidence for its use to treat genital herpes, psoriasis, dandruff and constipation. (Until 2002, its components were used in over-the-counter laxatives. The FDA required that aloe be removed due to lack of safety data.)

Unfortunately, there is no strong evidence supporting the use of aloe vera for other medical conditions. Areas lacking in scientific support include cancer prevention, use with chemotherapy or its side effects, canker sores, treatment of the common cold, dental conditions including gum disease and reduction of plaque, skin ulcers, high cholesterol, antioxidant and antibacterial properties, improvement of skin elasticity and wrinkle reduction, aid in digestion, and improved circulation.

Evidence has actually been found against the use of aloe vera for treatment of diaper rash, heart disease, liver disease, pressure ulcers, and most notably, wound healing. Although some early studies supported its topical use to heal burns and abrasions, later studies showed that the gel actually could inhibit the healing of some wounds.

And what about side effects? Using aloe vera topically doesn’t appear to cause significant side effects, but taking aloe vera orally may actually be dangerous. Consuming whole leaf extract has resulted in carcinogenic activity in rats (but not in humans). Abdominal cramps and diarrhea have been reported. Oral use of aloe vera can decrease the absorption of many medications. It may lower blood glucose levels, which can actually be effective for diabetics, but would require that other diabetic medication be carefully adjusted in order to maintain a critical delicate balance.

Aloe vera (like so many ancient natural herbs) does not possess potent medicinal powers simply because of its longevity. And, unlike the times of ancient Egypt, modern times often offer more effective products. While science and controlled studies clearly have their limitations, they do give us valuable guidance. Always discuss any herbal or supplemental products you are taking with your health care provider, in order to be aware of any interactions or side effects – and be aware that some popular herbs and supplements may simply offer little benefit.