The health benefits of topically applied aloe vera are long standing and well known. Aloe, an effective moisturiser that aids in healing the skin from cuts, burns and scrapes, provides benefits internally when ingested. While scientific evidence shows aloe vera's positive effects on immune diseases such as HIV, some dangers exist when drinking aloe vera juice. Overly large amounts of juice or chronic long-term use magnify these dangers.
Those with allergies to garlic, onion, tulips or other plants in the lily family should avoid aloe vera. Both topical and oral use of aloe vera by those who are allergic to it can cause skin irritation, hives, cramping and diarrhoea. A simple patch test by applying some pure aloe vera behind the ear will help to determine if an allergy is present. Those allergic to aloe should read the labels of any products they use, since aloe vera is present in a large number of topical skin products, as well as natural and herbal food and medicinal products.
Diarrhoea and Cramping
Whole leaf aloe vera juice contains aloe latex, a known laxative. According to the Mayo Clinic website, aloe vera causes diarrhoea and cramping that can lead to dangerous electrolyte imbalances, even if used for only a few days. The FDA, according to a November 5, 2002 final ruling, does not consider oral aloe vera to be a safe or effective laxative. Aloe vera's laxative properties are addictive and have a negative permanent effect on colon health that exacerbates constipation upon cessation of oral aloe vera.
According to the Mayo Clinic website, the use of oral aloe vera for a period of one year or more can increase the risk of colorectal cancer. The website Help for IBS noted that genotoxicity studies show that laxatives containing aloe vera pose this risk even when used as directed. Pseudomelanosis coli is a result of the long-term use of aloe vera, which is the culprit in causing colorectal cancer risk, according to the website Flora.
Blood Sugar Imbalances
The Mayo Clinic states that oral aloe vera has the ability to lower blood sugar. It should not be taken by those with diabetes or who are on drugs or supplements for blood sugar unless under medical supervision. Contraindicated drugs include hypoglycemics such as insulin, DiaBeta, glyburide, metformin and glipizide.
Death from kidney damage and severe hemorrhagic diarrhoea can result from toxic doses of oral aloe vera, as per the Mayo Clinic and Flora websites. Several days of oral consumption of aloe vera at a concentration of 1g per day or more is the lethal dose.