Aspartame is one artificial sweetener amongst many. It is perhaps one of the most often used artificial sweeteners out there. Many sugar free items that are aimed at Diabetics and people trying to diet to lose weight contain Aspartame. Just a few examples are: diet soft drinks, sugar free ice cream, iced tea, jams and jellies, sugar free yogurts, sugar free cookies, cereals, vitamins, and the list can go on and on.
Aspartame has actually been discovered to be quite bad for humans and really should be avoided. A lot of safer alternatives are out there now including things like stevia which is a natural sugar replacement that does not contain the harmful Aspartame.