Sodium sulfite is a white crystalline solid with the chemical formula Na2SO4. It is a widely used chemical compound that is used in various industries, including pharmaceuticals, food, and beverages. In the food industry, sodium sulfite is used as a preservative and to prevent oxidation of wine and other alcoholic beverages. It is also used as a reducing agent in metallurgy and in the production of dyes and paper. Sodium sulfite is generally safe for consumption in small amounts, but excessive ingestion can cause headaches, nausea, and other adverse effects.