Having sugar beyond certain limit poses u to threats like dental cavities, diabetes, heart problems, obesity etc. So many people have shifted to having artificial sweeteners instead of natural sugar but even that doesn't help us much. Artificial sweeteners are of different types like aspartame, saccharin, sucralose etc. and many people have allergies to these sweeteners. The most common side effect of these is diarrhea or headache. It also leads to some long term side effects like cancer. There have been known cases where people have been crippled due to over dose of aspartame. So as far as possible the sweeteners should be avoided. One should use natural sweeteners like stevia or the natural taste of some fruits and vegetables.