Aloe barbadensis Miller, Aloe vera, has enjoyed a long history of lay acceptance as an herbal remedy and is perhaps the most popular herbal remedy in use today. In recent times, the oral consumption of Aloe vera has been promoted as a prophylaxis and treatment to alleviate a variety of unrelated systemic conditions. The National Cancer Institute nominated Aloe vera for study under the National Toxicology Program, because of its widespread human exposure and because components in Aloe vera may possess tumor - promoting activities. Male and female F344/N rats and B6C3F1 mice were exposed to freeze dried (max. 6% moisture) and gamma-irradiated extracts of Aloe vera plant leaves in dr inking water for 14 days, 13 weeks, or 2 years.