Saccharin is a sweetener that contains no calories. It is a white crystalline powder, insoluble in water, heat stability is still controversial, its sweetness is 300 to 500 times that of sucrose, does not contain calories, and will have a slight bitter and metallic taste left on the tongue. Its sodium salts dissolve easily in water. LD50 is 5000 ~ 8000mg/kg; The daily safe intake tolerance (ADI) is 0 to 2.5mg/kg. Saccharin can be prepared by the reaction of o-sulfonic benzoic acid with ammonia. Mainly used in the food industry, can be used in toothpaste, cigarettes and cosmetics.