Pippa - if you mean that you've not heard of Truvia, it's just the Coca Cola / Cargill brand of an artificial sweetener made using the Stevia leaf. I think it was one of the 1st stevia-leaf sweeteners to hit the shelves. However, I saw a Tesco own sweetener on the shelf yesterday which is made with the stevia leaf & it's obviously much cheaper than Truvia.