If you use a pure extract or even better, grow your own, it is safe. It is a plant that happens to be quite sweet. The problems with fad sweeteners is that they are usually chemical (aspartame, saccharin, etc) and those are the ones that are toxic and cause problems. Or they are from "natural" sources and are so processed that there is nothing natural left, or what is left causes dangerous reactions in the body, like HFCS. Or something becomes popular, like agave nectar, and unscrupulous companies either label HFCS as agave or process actual agave in such a way that it has the same problems as HFCS.
So stick with the actual plant, or a pure extract. Skip products like Truvia, which have a fairy dust amount of stevia but are marketed as if they are pure stevia.
Read labels carefully.
Actually, I am suspicious of any product that has words in it like true, honest, natural, etc. These are usually the most deceptive advertisements of all.