Aloe vera refers to the Aloe barbadensis Miller plant. There are 420 different species of aloe. Aloe vera is approved by the Food and Drug Administration (FDA) as a food additive for flavoring. Aloe vera increases the average lifespan of rats and Drosophila fruit flies when added to food and drinking water. Furthermore, aloe vera gel reduces wrinkles in humans. The National Cancer Institute has raised concerns about the safety of aloe vera products. Aloe vera products that limit aloin to less than 5 ppm are safe for use. Products that contain high aloin content are not safe. Aloin is believed to be potentially carcinogenic. Aloe vera contains vitamins A, B (thiamine), B2 (riboflavin), C, beta carotene, vitamin E and F along with choline and folic acid. Aloe vera extract helps the digestion of sugars and fats, because it contains amylase and lipase. The plant also contains; sodium, aluminium, potassium, calcium, magnesium, chromium, iron, copper and zinc. Saponins make up 3% of the gel and have antiseptic properties. Aloe vera contains seven of the eight essential amino acids. Aloe contains phytochemicals such as organic acids salicylic, chrysophanic, succinic and uric, contains polysaccharides such as acemannen, enzymes such as glutathione peroxidase and various resins. Aloe vera can grow indoors and is easy to care for. To prepare aloe vera, remove the outer layers of the leaf, leaving the aloe gel or fillet. The gel can be pasteurized at 75-80°C for less than 3 minutes for stabilization. Higher temperatures can decompose the gel constituents. Yuji Ikeno et al. reported that permanent ingestion of aloe vera gel increases the average lifespan of Fischer rats. The animals used in this study... center of paper... are the anthraquinones present in the parenchyma cells of whole-leaf aloe vera. Aloe contains the anthraquinones barbaloin, isobarbaloin and anthronic C glycosides. The rats received aloe water that contained 60 ppm aloin. The NTP found no evidence of carcinogenic activity in mice. However, NTP has never conducted a study on the ingestion of bleached whole leaf extract in rats. Aloe vera is likely safe for use on the skin and is unlikely to cause skin cancer. Researchers at the University of Belgrade reported that aloe vera contains components that block the proliferation of cells associated with skin cancer. A protective component against skin cancer is emodin. Bottom line: Aloe vera gel or fillet is safe to use as a dietary supplement and potentially prolongs life. Unbleached whole leaf extract is potentially carcinogenic.