Aloe vera, which comes from a succulent plant, is sold as a juice and is added to foods, supplements, and skin care products. But just because it’s natural doesn’t mean it’s safe to consume.
Carefully conducted studies by the U.S. government concluded that there was “clear” evidence that aloe vera extracts caused intestinal cancers in male and female rats, but not mice, when consumed. (Applying aloe vera on the skin is not likely to cause harm.)
The form tested, called non-decolorized whole-leaf extract of aloe vera, contains more of the components that are suspected of being cancer-causing—aloin and other anthraquinones—than do many aloe vera products on the market, especially liquid products. (The outer leaf pulp of aloe leaves, known as the latex, contains anthraquinones).
However, it is not known for sure what components of aloe vera are responsible for the tumors.
The National Center for Complementary and Alternative Medicine (NCCAM) notes other possible concerns:
- People with diabetes who use glucose-lowering medication should be cautious about taking aloe vera by mouth since preliminary studies suggest it may lower blood glucose levels.
- The diarrhea caused by the laxative effect of aloe vera can decrease the absorption of many medications.
Given the possible risks, people should not eat or drink aloe vera. If you choose to consume it, look for products made with a charcoal filtration process to decolorize and remove anthraquinones, and monitored to ensure that aloin levels are low (e.g., 1 part per million or less).
Some solid or semi-solid products have much higher levels of aloin than liquids. However, low levels of aloin do not guarantee safety, since it is not known for sure exactly which components of aloe vera triggered cancers in rats.
This post was originally published in 2014 and is updated regularly.