Natural, Herbal, Zero Calorie Sweetening. Our Water Drops are lightly sweetened with all natural, plant sourced zero calorie stevia. Stevia rebaudiana, commonly known as sweetleaf, sweet leaf, sugarleaf, or simply stevia, is widely grown for its sweet leaves. Stevia has attracted attention with the rise in demand for low-carbohydrate, low-sugar sweeteners. Because stevia has a negligible effect on blood glucose it is attractive to people on carbohydrate-controlled diets.