Stevia Leaves are the leaves of the Stevia rebaudiana plant, which is a small shrub native to South America. The leaves are often used as a natural sweetener because they contain compounds called steviol glycosides, which are much sweeter than sugar but have no calories and do not raise blood sugar levels. Stevia leaves can be used fresh or dried to make tea, or they can be processed into a powder or liquid extract to be used as a sweetener in cooking and baking. Stevia is a popular alternative to sugar for people who are trying to reduce their calorie intake or manage blood sugar levels.