Scientific Publications by FDA Staff

Toxicol Sci 2013 Jan;131(1):26-39

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

Boudreau MD, Mellick P, Olson G, Felton R, Thorn B, Beland F

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, two-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/sex/group) at 0.5%, 1%, and 1.5%, and B6C3F1 mice (48/sex/group) at 1%, 2%, and 3%. Compared to controls, survival was decreased in the 1.5% dose group of female rats. Treatment-related neoplasms and non-neoplastic 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 the 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 of 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.