Aloe Vera
In plain terms
The clear inner-leaf gel is a soothing, moisturizing classic that is safe on skin and helps calm sunburn. The catch is the form: the cancer headlines are about drinking non-decolorized whole-leaf aloe, which carries a laxative compound called aloin, not about putting gel on your skin.
What the evidence shows
Aloe has to be split into its parts to make sense of its safety. The clear inner-leaf gel, the part used in skincare, is mostly water and soothing polysaccharides; it has a long record as a topical moisturizer and calms minor burns and irritation, with clinical support for speeding burn healing. The trouble lives in a different part of the plant. The yellow latex just under the rind contains aloin and related anthraquinones, which act as a harsh laxative, and non-decolorized whole-leaf extract that includes them is the form the warnings point to: the National Toxicology Program linked oral whole-leaf extract to intestinal tumors in rats, the international cancer agency rates it a possible human carcinogen, California lists it under Prop 65, and the FDA pulled aloe from over-the-counter laxatives. All of that is about swallowing the whole-leaf form, not about topical gel, and cosmetic aloe is the decolorized, aloin-stripped material with anthraquinones held to trace levels. So the verdict turns on form and route: topical inner-leaf gel is benign and soothing, while ingested non-decolorized whole-leaf extract is the one to skip. On skin, the only common issue is occasional contact allergy, more likely in people allergic to onion, garlic, or tulips.
On the label
Listed as aloe barbadensis leaf juice, gel, or extract. For skincare, the inner-leaf gel is the gentle, well-tolerated form. If you drink aloe, choose decolorized inner-leaf products that keep aloin low, and avoid non-decolorized whole-leaf juice or supplements.