Aloe Vera is a succulent plant species that is found only in cultivation, having no naturally occurring populations, although closely related aloes do occur in northern Africa. The species is frequently cited as being used in herbal medicine since the beginning of the first century AD. Extracts from A. Vera are widely used in the cosmetics and alternative medicine industries, being marketed as variously having rejuvenating, healing, or soothing properties. There is, however, little scientific evidence of the effectiveness or safety of Aloe Vera extracts for either cosmetic or medicinal purposes, and what positive evidence is available is frequently contradicted by other studies.
Aloe Vera is a stem less or very short-stemmed succulent plant growing to 60–100 cm tall, spreading by offsets. The leaves are thick and fleshy, green to grey-green, with some varieties showing white flecks on their upper and lower stem surfaces. The margin of the leaf is serrated and has small white teeth. Like other Aloe species,Aloe Vera a symbiosis that allows the plant better access to mineral nutrients in soil.
The natural range of A. Vera is unclear, as the species has been widely cultivated throughout the world. Naturalized stands of the species occur in the southern half of the Arabian Peninsula, through North Africa (Morocco, Mauritania, Egypt), as well as Sudan and neighboring countries, along with the Canary, Cape Verde, and Madeira Islands. Suggesting that a dry sclerophyl forest once covered large areas, but has been dramatically reduced due to desertification in the Sahara, leaving these few patches isolated. Several closely related (or sometimes identical) species can be found on the two extreme sides of the Sahara.
The species was introduced to China and various parts of southern Europe in the 17th century. The species is widely naturalized elsewhere, occurring in temperate and tropical regions of Australia, Barbados, Belize, Nigeria, Paraguay and the United States. The actual species' distribution has been suggested to be the result of human cultivation.
Aloe Vera has been widely grown as an ornamental plant. The species is popular with modern gardeners as a putatively medicinal plant and for its interesting flowers, form, and succulence. This succulence enables the species to survive in areas of low natural rainfall, making it ideal for rockeries and other low water-use gardens. The species is relatively resistant to most insect pests, though spider mites, mealy bugs, scale insects, and aphid species may cause a decline in plant health. In pots, the species requires well-drained, sandy potting soil and bright, sunny conditions; however, Aloe plants can burn under too much sun or shrivel when the pot does not drain the rain. The use of a good-quality commercial propagation mix or packaged "cacti and succulent mix" is recommended, as they allow good drainage. Terra cotta pots are preferable as they are porous. Potted plants should be allowed to completely dry prior to dewatering. When potted, aloes become crowded with "pups" growing from the sides of the "mother plant", they should be divided and repotted to allow room for further growth and help prevent pest infestations. During winter, Aloe Vera may become dormant, during which little moisture is required. In areas that receive frost or snow, the species is best kept indoors or in heated glasshouses. Large-scale agricultural production of Aloe Vera is undertaken in Australia, Bangladesh, Cuba, the Dominican Republic, China, Mexico, India, Jamaica, Kenya, Tanzania and South Africa, along with the USA to supply the cosmetics industry with Aloe Vera gel.
Preparations made from Aloe Vera are often referred to as "aloe Vera". Scientific evidence for the cosmetic and therapeutic effectiveness of aloe Vera is limited and when present is frequently contradictory. Despite this, the cosmetic and alternative medicine industries regularly make claims regarding the soothing, moisturizing, and healing properties of aloe Vera. Aloe Vera gel is used as an ingredient in commercially available lotions, yogurt, beverages, and some desserts, although at certain doses, it has toxic properties when used either for ingested or topical applications. Other uses for extracts of Aloe Vera include the dilution of semen for the artificial fertilization of sheep, as a fresh food preservative, or for water conservation in small farms. It has also been suggested that befouls could be obtained from Aloe Vera seeds. Aloe is also used as a food substance, possibly for its gelling properties.
Aloe Vera, called kathalai in Ayurvedic medicine, is used as a multipurpose skin treatment. This may be partly due to the presence of saponin, a chemical compound that acts as an antimicrobial agent.
Two 2009 reviews of clinical studies determined that all were too small and faulty to allow strong conclusions to be drawn from them, but concluded, "there is some preliminary evidence to suggest that oral administration of aloe Vera might be effective in reducing blood glucose in diabetic patients and in lowering blood lipid levels in hyperlipidaemia. The topical application of aloe Vera does not seem to prevent radiation-induced skin damage. It might be useful as a treatment for genital herpes and psoriasis. The evidence regarding wound healing is contradictory. More and better trial data are needed to define the clinical effectiveness of this popular herbal remedy more precisely." One of the reviews found that Aloe has not been proven to offer protection for humans from sunburn, suntan, or other damage from the sun.
A 2007 review of aloe Vera's use in burns concluded, "Cumulative evidence tends to support that aloe Vera might be an effective interventions used in burn wound healing for first- to second-degree burns. Further, well-designed trials with sufficient details of the contents of aloe Vera products should be carried out to determine the effectiveness of aloe Vera. Topical application of aloe Vera may also be effective for genital herpes and psoriasis.