Clear evidence of carcinogenic activity by a whole-leaf extract of Aloe barbadensis miller (aloe vera) in F344/N rats

Toxicol Sci. 2013 Jan;131(1):26-39. doi: 10.1093/toxsci/kfs275. Epub 2012 Sep 11.


Aloe barbadensis Miller (Aloe vera) is an herbal remedy promoted to treat a variety of illnesses; however, only limited data are available on the safety of this dietary supplement. Drinking water exposure of F344/N rats and B6C3F1 mice to an Aloe vera whole-leaf extract (1, 2, and 3%) for 13 weeks resulted in goblet cell hyperplasia of the large intestine in both species. Based upon this observation, 2-year drinking water studies were conducted to assess the carcinogenic potential of an Aloe vera whole-leaf extract when administered to F344/N rats (48 per sex per group) at 0.5, 1, and 1.5%, and B6C3F1 mice (48 per sex per group) at 1, 2, and 3%. Compared with controls, survival was decreased in the 1.5% dose group of female rats. Treatment-related neoplasms and nonneoplastic lesions in both species were confined primarily to the large intestine. Incidences of adenomas and/or carcinomas of the ileo-cecal and cecal-colic junction, cecum, and ascending and transverse colon were significantly higher than controls in male and female rats in the 1 and 1.5% dose groups. There were no neoplasms of the large intestine in mice or in the 0 or 0.5% dose groups of rats. Increased incidences of mucosa hyperplasia of the large intestine were observed in F344/N rats, and increased incidences of goblet cell hyperplasia of the large intestine occurred in B6C3F1 mice. These results indicate that Aloe vera whole-leaf extract is an intestinal irritant in F344/N rats and B6C3F1 mice and a carcinogen of the large intestine in F344/N rats.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Administration, Oral
  • Aloe / chemistry*
  • Animals
  • Body Weight / drug effects
  • Carcinogenicity Tests
  • Dose-Response Relationship, Drug
  • Female
  • Hyperplasia
  • Intestinal Mucosa / drug effects*
  • Intestinal Mucosa / pathology
  • Intestinal Neoplasms / chemically induced*
  • Intestinal Neoplasms / pathology
  • Intestine, Large / drug effects*
  • Intestine, Large / pathology
  • Male
  • Mice
  • Mice, Inbred Strains
  • Plant Extracts / isolation & purification
  • Plant Extracts / toxicity*
  • Plant Leaves / chemistry
  • Rats
  • Rats, Inbred F344
  • Species Specificity
  • Survival Analysis


  • Plant Extracts