The succulent aloe plant has been valued since prehistoric times for the treatment of burns, wound infections, and other skin problems. Medicinal aloe is pictured in an ancient cave painting in South Africa, and Alexander the Great is said to have captured an island off Somalia for the sole purpose of possessing the luxurious crop of aloe found there.
Most uses of aloe refer to the gel inside its cactus-like leaves. However, the skin of the leaves themselves can be condensed to form a sticky substance known as drug aloe or aloes. It is a powerful laxative, but it is seldom used because its effects are unpleasant. The uses described below are intended to refer only to aloe gel, not to drug aloe. However, to make matters trickier, some aloe gel products contain small amounts of drug aloe, and it is possible that this contaminant is the actual source of benefits seen in some studies. 20,21
We suspect millions of people would swear by their own experience that applying aloe to the skin can drastically reduce the time it takes for burns (including sunburns ) to heal. But, there is conflicting evidence regarding aloe's benefits. Some studies suggest that aloe is not effective for treating sunburn and may actually impair the healing of second-degree burns. 1,2 However, a small randomized trial involving 30 people with second-degree burns found that treatment with aloe cream resulted in faster healing time compared to silver sulfadiazine cream, a common treatment for burns. 39
Aloe also appears to be ineffective for treating the burn-like skin damage caused by radiation therapy for cancer . In a double-blind, placebo-controlled study of 194 women undergoing radiation therapy for breast cancer, use of aloe gel failed to protect the skin from radiation-induced damage. 7 Lack of benefit was also seen in an open trial of 225 women. 22 One study evaluated aloe soap in 73 men and women undergoing radiation therapy for various forms of cancer and, overall, failed to find benefit except possibly at the highest doses. 23 Another study failed to find aloe gel helpful for mouth inflammation caused by radiation therapy for head and neck cancer. 27
Besides its use for burns, aloe has been widely recommended for aiding wound healing . Results of test tube and animal studies of aloe for wounds have been positive. 3-5,24,25 And a small randomized study involving 49 people recovering from hemorrhoid surgery found that aloe cream reduced pain and hastened wound healing. 37 But, one clinical report suggests that aloe can actually impair the healing of severe wounds. 6 Also, a review of 7 trials involving 347 people did not find evidence that aloe can improve wound healing. 41
Aloe gel has also been tried as a treatment to be taken internally by mouth. Two studies suggest that that aloe gel taken in this way might be helpful for type 2 diabetes . 8,9 One study found possible benefits for ulcerative colitis . 28
Oral aloe is also sometimes recommended as an aid in the treatment of asthma , stomach ulcers , and general immune support , but there is no meaningful evidence that it is effective for any of these purposes.
One of the constituents of aloe gel, acemannan, has shown some promise in test tube and animal studies for stimulating immunity and inhibiting the growth of viruses. 10-12 These finding have led to the suggestion that acemannan can help HIV infection . However, the one reported double-blind, placebo-controlled trial failed to show benefits. 26
A 2-week, double-blind, placebo-controlled trial enrolled 60 men with active genital herpes . 13 Participants applied aloe cream (0.5% aloe) or placebo cream 3 times daily for 5 days. Use of aloe cream reduced the time necessary for lesions to heal (4.9 days versus 12 days), and also increased the percentage of individuals who were fully healed by the end of 2 weeks (66.7% versus 6.7%).
A previous double-blind, placebo-controlled study by the same author, enrolling 120 men with genital herpes, found that cream made from aloe was more effective than pure aloe gel or placebo. 14
Seborrhea is a fairly common skin condition, leading to oily, red, and scaly eruptions in such areas as the eyebrows, eyelids, nose, ear, upper lip, chest, groin, and chin. A double-blind, placebo-controlled study of 44 individuals found that 4 to 6 weeks of treatment with aloe ointment could significantly reduce symptoms of seborrhea. 16
There are contradictory results regarding the effectiveness of aloe cream for treating psoriasis.
According to a double-blind study that enrolled 60 men and women with mild to moderate symptoms of psoriasis , aloe cream may be helpful for this chronic skin condition. 15 Participants were treated with either topical aloe extract (0.5%) or a placebo cream, applied 3 times daily for 4 weeks. Aloe treatment produced significantly better results than placebo, and these results were said to endure for almost a year after treatment was stopped. The study authors also reported a high level of complete "cure," but what exactly they meant by this was not reported clearly. Another study found that aloe cream was more effective than triamcinolone acetonide, a corticosteroid that is applied to the skin. 38 For 8 weeks, 80 patients with mild to moderate psoriasis were randomized to receive aloe cream or 0.1% triamcinolone acetonide. Those in the aloe group had a greater reduction in their symptoms compared to the corticosteroid group.
However, another study failed to reproduce these favorable results. 31 Over four weeks of treatment, marked improvement was seen in 72.5% of skin patches treated with aloe, but 82% of those treated with placebo. This was a statistically significant difference in favor of placebo.
Lichen planus is a chronic skin condition characterized by itchy, flat, scaly patches. It can occur in various parts of the body, including the wrists, legs, trunk, mouth, and vagina.
One study evaluated the potential value of aloe vera as a topical treatment for oral lichen planus. 35 In this double-blind, placebo controlled study of 54 people with oral lichen planus, use of aloe vera gel was significantly more effective than placebo in alleviating symptoms. In another study involving 34 women with lichen planus of the vulva (just outside the vagina), aloe vera led to significantly more improvement than placebo. 36
Evidence from two human trials suggests that aloe gel can improve blood sugar control in individuals with type 2 diabetes .
A single-blind, placebo-controlled trial evaluated the potential benefits of aloe in either 72 or 40 individuals with diabetes (the study report appears to contradict itself). 17 The results showed significantly greater improvements in blood sugar levels among those given aloe over the 2-week treatment period.
Another single-blind, placebo-controlled trial evaluated the benefits of aloe in individuals who had failed to respond to the oral diabetes drug glibenclamide. 18 Of the 36 individuals who completed the study, those taking glibenclamide and aloe showed definite improvements in blood sugar levels over 42 days as compared to those taking glibenclamide and placebo.
A double-blind randomized control trial of 67 patients with diabetes and high cholesterol compared oral aloe vera gel to placebo. All patients were also taking diabetes medications glyburide and metformin. After 2 months, aloe was associated with lowered fasting blood glucose, HbA1c levels (an indicator of overall blood sugar control), total cholesterol, and LDL (“bad”)cholesterol. 42
Although these are promising results, large studies that are double- rather than single-blind will be needed to establish aloe as an effective treatment for hypoglycemia.
In a double-blind, placebo-controlled study of 44 people with active ulcerative colitis , use of oral aloe gel at a dose of 100 ml twice daily for 4 weeks appeared to improve both subjective symptoms and objective measurements of disease severity. 29 About half of the people given aloe showed response to treatment; about 30% experienced full remission. Benefits occurred only rarely in the placebo group. However, this was a small study, and its results can't be taken as conclusive.
Topical aloe vera cream typically contains 0.5% aloe and is applied three times daily.
For the treatment of diabetes, a dosage of 1 tablespoon of aloe juice twice daily has been used in studies.
Other than occasional allergic reactions, no serious problems have been reported with aloe gel, whether used internally or externally. However, comprehensive safety studies are lacking. Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established.
Keep in mind that if aloe is used as a treatment for diabetes, and it proves effective, blood sugar levels could fall too low, necessitating a reduction in medication dosage. Close monitoring of blood sugar levels is, therefore, advised.
In addition, there is one report of an herb-drug interaction between aloe and the anesthesia drug sevoflurane, in which it appeared that aloe may have increased sevoflurane's "blood thinning" effect. 30
Another isolated report appears to connect aloe to liver inflammation in one person. 34 (Since aloe does not appear to possess any liver toxicity in general, this report would seem to suggest an “idiosyncratic,” in other words, a highly personal reaction to the herb.)
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- EBSCO CAM Review Board
- Reviewed: 12/2015
- Updated: 12/15/2015
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