Some side effects of Sweet'N Low, a brand name for a saccharin sweetner, include mild to moderate nausea, itching, hives and light sensitivity, according to LabDoor.com. Saccharin is a sulfonamide, and individuals allergic to sulfa drugs may experience difficulty breathing, headaches, eczema and diarrhea, according to MedicineNet.
The U.S. Food and Drug Administration does not have research supporting the claim that infant formulas containing saccharin cause muscle dysfunction and irritability, and so the agency has not limited use of the sweetener by pregnant women, infants and children, explains MedicineNet. As of 2000, the National Toxicology Program of the National Institutes of Health no longer considers products containing saccharin to be possibly carcinogenic. The FDA has approved five artificial sweeteners including saccharin, which is selected frequently as the safest. Sween'N Low was first used in the United States in 1957, according to the company's website.