Wikipedia Article About Stevia extract on Wikipedia Stevia extract is a natural sweetener. Whole foods proponents draw a distinction between consuming (and safety testing) only parts, such as stevia extracts and isolated compounds like stevioside, versus the whole herb. In his book Healing With Whole Foods, Paul Pitchford cautions, "Obtain only the green or brown [whole] stevia extracts or powders; avoid the clear extracts and white powders, which, highly refined and lacking essential phyto-nutrients, cause imbalance".