What effect does oral aloe vera have on diabetes?

A meta-analysis of studies in people with diabetes and pre-diabetes has shown that oral aloe vera use was associated with significant decreases in both fasting blood glucose (FBG) and hemoglobin A1c (HbA1c). The data indicate that people with a FBG >200 mg/dL may benefit the most, according to an article in The Journal of Alternative and Complementary Medicine, a peer-reviewed publication from Mary Ann Liebert, Inc., publishers. The article is available free for download on The Journal of Alternative and Complementary Medicine website until July 29, 2016.
In the article "Reduction of Fasting Blood Glucose and Hemoglobin A1c Using Oral Aloe Vera: A Meta-Analysis," William Dick, Emily Fletcher, and Sachin Shah, David Grant Medical Center, Travis Air Force Base, Fairfield, CA and Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA describe their analysis of data from nine studies to assess the effectiveness of oral aloe vera consumption in diabetes. They report significant reductions in FBG and HbA1c of 46.6 mg/dL and 1.05%, respectively, and review the proposed mechanisms that could account for these anti-diabetic effects.
Source: The Journal of Alternative and Complementary Medicine