When taken orally, aloe vera is said to cure a lot of ailments, including “alopecia, Alzheimer’s disease, congenital heart failure, depression, glaucoma, hemorrhoids, hepatitis, multiple sclerosis, and varicose veins.” But of these, none have been subject to clinical trials. On the other hand, there have been studies on aloe vera’s efficacy in the treatment of diabetes mellitus, constipation, as well as ulcers and inflammation of the gastrointestinal tract.
The sap of the aloe vera is a commonly used laxative and treatment for constipation. According to a study published in the 2nd edition of Herbal Medicine: Biomolecular and Clinical Aspects, “Aloe vera laxative preparations have been approved by the German Commission E governmental regulatory agency for use in the treatment of constipation as a second-line agent; however, aloe latex is no longer recognized as an over-the-counter drug by the U.S. Food and Drug Administration due to a lack of sufficient data to establish its safety for use as a laxative.”
Numerous studies have been done on the efficacy of aloe vera in lowering blood glucose and lipids, and these studies point to the possible use of aloe vera in the management of both diabetes and heart disease.
Though there are many benefits, the safety and efficacy of aloe vera are still difficult to determine because there are no guidelines to standardize the commercially available aloe vera preparations. It is generally accepted, however, that aloe vera is not associated to significant side effects with topical use.
Contraindications to using aloe vera include having known allergy to plants in the Liliaceae family (such as onions, garlic, and turnips); pregnancy (because it has not been studied whether or not aloe vera is safe for the baby in the womb); and having renal or cardiac disease (aloe vera’s laxative properties can cause electrolyte imbalance, affecting the bowels and the body’s potassium supply).
The meta-analysis in Herbal Medicine also lists among aloe vera’s contraindications the possible herbal-drug interactions: “Potential interactions have been suggested for aloe vera and drugs that may alter electrolyte balance, such as thiazide diuretics and corticosteroids. Possible hypokalemia-related arrhythmia suggests a potential herb-drug interaction with cardiac glycosides. Caution is warranted in patients taking hypoglycemic agents as interactions with aloe vera gel have been reported.”