Truvia natural sweetener is a commercial brand of stevia manufactured by Cargill, Inc. Stevia is an herb whose extract is many times sweeter than sugar. It is on the FDA's list of substances that are "generally recognized as safe."
Stevia is calorie-free and does not raise blood sugar levels, making it an alternative for those on low-glycemic and weight-loss diets. It can be used in cooking and baking and as a tabletop sugar replacement.
The FDA found "no basis to object" to the use of stevia preparations in food, but it is still a controversial product. The Mayo Clinic reports that stevia is probably safe in moderate amounts, but recommends that pregnant and breastfeeding women avoid its use.
The FDA has approved the use of stevia in commercial preparations manufactured by several companies. Brand names in addition to Truvia include Good & Sweet, Sun Crystals and Pure Via.