Vogler, B. K., & Ernst, E. (1999). Aloe vera: a systematic review of its clinical effectiveness. British Journal of General Practice, 49, 823–828.

To summarize all controlled clinical trials on aloe vera preparations to provide evidence for or against its clinical effectiveness.

Databases searched were MEDLINE, EMBASE, Biosis, and Cochrane Library.

Search keywords were complementary medicine, aloe vera, and review. 

Experts working in the area were contacted and asked for published and unpublished controlled clinical trials and their own papers and files. All databases were searched from their inception to May 1998.

Studies were included if they were controlled clinical trials.

Studies were excluded if they were not performed on aloe vera mono-preparation and if they were designed only on a certain pharmacologic constituent of the aloe vera plant.

Data were extracted in a predefined fashion, and the methodologic quality of the study was assessed using the Jadad scoring system.

Ten trials met the inclusion criteria and were included. Three clinical studies were excluded because of not being performed on aloe vera mono-preparation or use of only a constituent of the plant. No unpublished studies were found.

• The study included 740 participants from 10 clinical trials.
• Conditions included were arthritis, asthma, Candida, chronic fatigue syndrome, lupus erythematosus, sports injuries, ulcers, digestive disorders, and various skin conditions.
• Aloe vera was used as as a topical agent in six studies and was administered orally in four studies. Of these studies, two examined topical aloe vera for prevention or mitigation of radiodermatitis.

• In the studies regarding use for radiodermatitis, no difference was reported between the treatment group and the placebo group.
• Aloe vera might be useful in patients after dermabrasion, mild to moderate plaque-type psoriasis, and treatment of initial genital herpes episodes, with shortened time to healing.
• In postoperative gynecology surgery patients with wound complications, standard wound care was superior to aloe vera. It was concluded that evidence regarding would healing was contradictory.
• All studies had methodologic flaws and did not achieve high scores for quality of the study design. Flaws included lack of randomization, lack of blinding, small sample size, lack of intention to treat analysis, and lack of power calculations.
• Trials tended to originate from the same research groups, and independent replications were lacking. As a result, firm conclusions from the review cannot be drawn.
• Oral aloe vera may have had some effect in reducing blood glucose levels in combination with antidiabetic therapy and in influencing lower serum lipids in one study.

No firm conclusions were drawn from the review because of multiple methodologic studies. It was concluded that topical application does not seem to prevent radiation-induced skin damage. No statistical significance findings from studies were reported.

The authors only included abstracts of controlled trials but then drew no conclusions about these findings because they were only abstracts.

More and better clinical trial data are needed to define the clinical effectiveness of this remedy.