The leaves of the stevia plant contain unique materials known as steviol glycosides, which are part of the sweetest part of the stevia plant and more than 200 times sweeter than sugar without all the calories. The stevia leaf extracts we use contain steviol glycosides known as rebaudiosides (Reb A, Reb D, and Reb M). An extraction process is needed to get these sweet rebaudiosides separated from the other parts of the leaf, which can have bitterness and other flavors.