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/Toxicity[edit]
In 2011, the NTP carried out a series of short- and long-term carcinogenicity studies of a nondecolorized whole leaf extract of Aloe barbadensis miller (Aloe vera) in rats and mice, in which the extracts were fed to the rodents in drinking water.[4] The studies found "clear evidence of carcinogenic activity" in the rats, but "no evidence of carcinogenic activity" in the mice. Both the mice and rats had increased amounts of noncancerous lesions in various tissues. The NTP believes further studies of oral preparations of aloe are important, as are studies of the oral exposure of humans to aloe; topical preparations are still considered safe.[4]
Oral ingestion of Aloe vera may also cause diarrhea, which in turn can lead to electrolyte imbalance, kidney dysfunction, dry mouth, headache, and nausea, while topical application may induce contact dermatitis, erythema, or phototoxicity.[4][53]