Stevia itself is a completely natural and safe substance, the extract of stevia leaf. FOS- Inulin is used with success by some, and not tolerated well by others. Looks like this particular product is a much higher percentage of Inulin than Stevia. I've picked up a box myself and am trying it out right now, since I'm suspecting the fiber supplement I had been using to be the cause of my bloating woes. But if you want to just use stevia you can get it at your local health, co-op, Vitamin Shoppe, or what-have-you.