Aloe (Aloe vera)
Background
Transparent gel from the pulp of the meaty leaves of Aloe vera has been used topically for thousands of years to treat wounds, skin infections, burns, and numerous other dermatologic conditions. Dried latex from the inner lining of the leaf has traditionally been used as an oral laxative.
There is strong scientific evidence in support of the laxative properties of aloe latex, based on the well-established cathartic properties of anthroquinone glycosides (found in aloe latex). However, aloe's therapeutic value compared with other approaches to constipation remains unclear.
There is promising preliminary support from laboratory, animal, and human studies that topical aloe gel has immunomodulatory properties which may improve wound healing and skin inflammation.
Synonyms
Acemannan, Aloe africana , Aloe arborescens Miller, Aloe barbadensis , Aloe capensis , Aloe ferox , aloe latex, aloe mucilage, Aloe perfoliata , Aloe perryi Baker, Aloe saponaria , Aloe spicata , Aloe vulgari , Barbados aloe, bitter aloe, burn plant, Cape aloe, Carrisyn, hirukattali, Curaçao aloe, elephant's gall, first-aid plant, Ghai kunwar, Ghikumar, Hsiang-Dan, jelly leek, kumari, lahoi, laloi, lily of the desert, Lu-Hui, medicine plant, Mediterranean aloe, miracle plant, mocha aloes, musabbar, natal aloes, nohwa, plant of immortality, plant of life, rokai, sabilla, Savila, Socotrine aloe, subr, true aloe, Venezuela aloe, Za'bila, Zanzibar aloe.
Evidence
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
| Uses based on scientific evidence | Grade* |
Constipation (laxative) Dried latex from the inner lining of aloe leaves has been used traditionally as a laxative taken by mouth. Although few studies have been conducted to assess this effect of aloe in humans, the laxative properties of aloe components such as aloin are well supported by scientific evidence. A combination herbal remedy containing aloe was found to be an effective laxative, although it is not clear if this effect was due to aloe or to other ingredients in the product. Further study is needed to establish dosing and to compare the effectiveness and safety of aloe with other commonly used laxatives. | A |
Genital herpes Limited evidence from human studies suggests that extract from Aloe vera in a hydrophilic cream may be an effective treatment of genital herpes in men (better than aloe gel or placebo). Additional research is needed in this area before a strong recommendation can be made. | B |
Psoriasis vulgaris Early evidence suggests that extract from aloe in a hydrophilic cream may be an effective treatment of psoriasis vulgaris. Additional research is needed in this area before a strong recommendation can be made. | B |
Seborrheic dermatitis (seborrhea, dandruff) Early study of aloe lotion suggests effectiveness for treating seborrheic dermatitis when applied to the skin. Further study is needed in this area before a strong recommendation can be made. | B |
Cancer prevention There is preliminary evidence that oral aloe may reduce the risk of developing lung cancer. Further study is needed in this area to clarify if it is aloe itself or other factors that may cause this benefit. | C |
Canker sores (aphthous stomatitis) There is weak evidence that treatment of recurrent aphthous ulcers of the mouth with aloe gel may reduce pain and increase the amount of time between the appearance of new ulcers. Further study is needed before a recommendation can be made. | C |
Diabetes (type 2) Study results are mixed. More research is needed to explore the effectiveness and safety of aloe in diabetics. | C |
HIV infection Without further human trials, the evidence cannot be considered convincing either in favor or against this use of aloe. | C |
Skin burns Preliminary evidence suggests that aloe may be effective in promoting healing of mild to moderate skin burns. Further study is needed in this area. | C |
Ulcerative colitis There is limited but promising research of the use of oral aloe vera in ulcerative colitis (UC), compared to placebo. It is not clear how aloe vera compares to other treatments used for UC. | C |
Wound healing Study results of aloe on wound healing are mixed with some studies reporting positive results and others showing no benefit or potential worsening of the condition. Further study is needed, since wound healing is a popular use of topical aloe. | C |
Mucositis There is preliminary evidence that oral aloe vera does not prevent or improve mucositis (mouth sores) associated with radiation therapy. | D |
Pressure ulcers One well-designed human trial found no benefit of topical acemannan hydrogel (a component of aloe gel) in the treatment of pressure ulcers. | D |
Radiation dermatitis Reports in the 1930s of topical aloe's beneficial effects on skin after radiation exposure lead to widespread use in skin products. Currently, aloe gel is sometimes recommended for radiation-induced dermatitis, although scientific evidence suggests a lack of benefit in this area. | D |
*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Alopecia (hair loss), Alzheimer's disease, antimicrobial, antioxidant, arthritis, asthma, bacterial skin infections, bowel disorders, chronic fatigue syndrome, chronic leg wounds, congestive heart failure, damaged blood vessels, elevated cholesterol or other lipids, frostbite, heart disease prevention, hepatitis, inflammatory bowel disease (IBS), kidney or bladder stones, leukemia, lichen planus, Merkel cell carcinoma, parasitic worm infections, protection against some chemotherapy side effects, scratches or superficial wounds of the eye, stomach ulcers, systemic lupus erythematosus (SLE), tic douloureux, untreatable tumors, vaginal contraceptive, yeast infections of the skin.
Dosing
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
Pure Aloe vera gel is often used liberally on the skin. Creams and lotions are also available. There are no reports that using aloe on the skin causes absorption of chemicals into the body that may cause significant side effects. Skin products are available that contain aloe alone or aloe combined with other active ingredients.
The dose often recommended constipation is the minimum amount to maintain a soft stool, typically 0.04-0.17 gram of dried juice (corresponds to 10-30 milligrams hydroxyanthraquinones) by mouth. As an alternative, in combination with celandin (300 milligrams) and psyllium (50 milligrams), 150 milligrams of the dried juice per day of aloe has been found effective as a laxative in research.
Cases of death have been associated with Aloe vera injections under unclear circumstances. Oral or injected use is not recommended due to lack of safety data.
Children (younger than 18 years)
Topical (skin) use of aloe gel in children is common and appears to be well tolerated. However a dermatologist and pharmacist should be consulted before starting therapy.
Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
People with known allergy to garlic, onions, tulips, or other plants of the Liliaceae family may have allergic reactions to aloe. Individuals using aloe gel for prolonged times have developed allergic reactions including hives and eczema-like rash.
Pregnancy and Breastfeeding
Although topical (skin) use of aloe is unlikely to be harmful during pregnancy or breastfeeding, oral (by mouth) use is not recommended due to theoretical stimulation of uterine contractions. It is not known whether active ingredients of aloe may be present in breast milk. The dried juice of aloe leaves should not be consumed by breastfeeding mothers.
Interactions
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
Aloe taken by mouth may lower blood sugar levels. Caution is advised when taken with medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. In addition, insulin may add to the decrease in blood potassium levels that can occur with aloe.
Due to lowering of potassium levels that may occur when aloe is taken by mouth, the effectiveness of heart medications such as digoxin and digitoxin, and of other medications used for heart rhythm disturbances, may be reduced. The risk of adverse effects may be increased with these medications due to low potassium levels.
Caution should be used in patients taking loop diuretics, such as Lasix® (furosemide), that increase the elimination of both fluid and potassium in the urine. Combined use may increase the risk of potassium depletion and of dehydration.
Use of aloe with laxative drugs may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH.
Application of aloe to skin may increase the absorption of steroid creams such as hydrocortisone. In addition, oral use of aloe and steroids such as prednisone may increase the risk of potassium depletion.
There is one report of excess bleeding in a patient undergoing surgery receiving the anesthetic drug sevoflurane, who was also taking aloe by mouth. It is not clear that aloe or this specific interaction was the cause of bleeding.
Preliminary reports suggest that levels of AZT, a drug prescribed in HIV infection, may be increased by intake of aloe.
Interactions with Herbs and Dietary Supplements
Based on the laxative properties of oral aloe, prolonged use may result in potassium depletion. This may be worsened by the use of licorice root.
Theoretically, use of oral aloe and other laxative herbs may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH.
Oral aloe can reduce blood sugar. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
Aloe may increase the absorption of vitamin C and vitamin E.
Methodology
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Jennifer Armstrong, PharmD (University of Rhode Island); Ethan Basch, MD (Memorial Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai Medical Center, NY); Steve Bent, MD (University of California, San Francisco); Cynthia Dacey, PharmD (Northeastern University); Sean Dalton, MD, PhD, MPH (Harvard University); Ivo Foppa, MD, ScD (Harvard University); Paul Hammerness, MD (Harvard Medical School); Catherine Kirkwood, MPH, CCCJS-MAC (MD Anderson Cancer Center, University of Texas); David Sollars, M.Ac, H.M.C. (New England School of Acupuncture); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).
