Stevioside extracted from Stevia rebaudiana is pure natural with zero calories, but its sweetness is 300 times that of sucrose, making it a substitute for the first and second generation sugar. So it is called natural zero card. This kind of sugar is developed by a doctor, so it is called natural zero-calorie sugar in dr. zhang. Black tea and green tea produced by this sugar source will not get fat after being drunk. Known as dr. zhang natural zero-calorie green tea and black tea.