In addition to the information which can be found on stevia via PubMed, here's some more information about stevia from Healthnotes (note to access Healthnotes go to a site such as http://www.newseasonsmarket.com
and click on the Healthnotes link). A Google search also brings up quite a few hits as well.
Common name: Sweetleaf
Botanical name: Stevia rebaudiana
Parts used and where grown
The stevia plant originally came from the rain forests of Brazil and Paraguay. It is now grown in those areas, as well as in Japan, Korea, Thailand, and China. It is most widely used as a non-sugar sweetener in food and drink, particularly because it does not appear to have any calories or affect on blood sugar like most natural sweeteners (like sugar or honey). The leaf is used in herbal preparations.
Historical or traditional use (may or may not be supported by scientific studies)
The native peoples in South America used stevia primarily as a sweetener, a practice adopted by European colonists. The indigenous tribes also used stevia to treat diabetes (1). During World War II, stevia was grown in England as a sugar substitute. The greatest use of stevia as a sweetener today can be found in Japan.
Various glycosides, particularly stevoside, give stevia its sweetness. Stevoside is between 100 and 200 times sweeter than sugar. Early reports suggested that stevia might reduce blood sugar (and therefore potentially help with diabetes) (2) although this has not been confirmed in all reports (3).
How much is usually taken?
Less than 1 gram per day can be used effectively as a sweetener. Usually, the powdered herb is added directly to tea or to food.
Are there any side effects or interactions?
Extensive reviews of human and animal data indicate stevia to be safe (4). Stevia accounts for nearly 40% of the sweetener market in Japan and is commonly used in various parts of South America (5).
At the time of writing, there were no well-known drug interactions with stevia.
References for Stevia:
1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 478–80.
2. Curi R, Alvarez M, Bazotte RB, et al. Effect of Stevia rebaudiana on glucose tolerance in normal adult humans. Braz J Med Biol Res 1986;19:771–4.
3. White JR Jr, Kramer J, Campbell RK, Bernstein R. Oral use of a topical preparation containing an extract of Stevia rebaudiana and the chrysanthemum flower in the management of hyperglycemia. Diabetes Care 1994;17:940.
4. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 478–80.
5. Blumenthal M. FDA rejects AHPA stevia petition. Whole Foods 1994:Apr;61–4.