Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na2S2O5. The name is sometimes referred to as disodium (metabisulfite, etc). It is used as a disinfectant, antioxidant and preservative agent. It is used as a food additive, mainly as a preservative and is sometimes identified as E223. It may cause allergic reactions in those who are sensitive to sulfites, including respiratory reactions in asthmatics as well as in those who do not identify with the condition. It is present in many dilutable squashes (i.e. fruit juice concentrates) and in candy bars such as Mounds. Sodium metabisulfite and potassium metabisulfite are the primary ingredients in Campden tablets, used for wine and beer making. The acceptable daily intake is up to 0.7 mg per kg of body weight. Sodium metabisulfite has no side effects; it is oxidised in the liver to harmless sulfate and excreted in the urine.