Steviol glycosides are found in the leaves of a scrub plant native to the sub-tropical regions of South America, Stevia rebaudiana Bertoni sp. Reports show that the biosynthesis and accumulation of steviol glycosides also occurs in two other plants: the Chinese blackberry Rubus suavissimus S.K. Lee, also known as Chinese sweet leaf and the Japanese Angelica Keiskei Koidz, or aka. Tomorrow's Leaf.^1–5  S. rebaudiana produces several steviol glycosides, of which stevioside and rebaudioside A are the most abundant.⁶  They are based on a common diterpene aglycone core structure, steviol and are (poly)glycosylated on C₁₃ or C₁₉ with a variety of glucose moieties. The physiological pathway involved in the signal transduction of these molecules has only recently been identified. In this chapter, we aim to give an overview how steviol glycosides evoke their physiological effects.