The main ingredient of sodium chloride injection is sodium chloride. There are different concentrations of sodium chloride injection, such as 0.45%, 0.9%, 3%-5% sodium chloride injection. 0.9% sodium chloride injection is also known as saline because it is an isotonic solution of human plasma, so it can be widely used as a solvent for a variety of drugs for intravenous infusion. Sodium chloride injection can be used orally as well as externally, and is most commonly used for intravenous infusion. In addition to being a drug solvent, sodium chloride injection can also be used for massive rehydration in dehydrated patients. In case of hypertonic dehydration, 0.45% sodium chloride injection should be infused. For isotonic dehydration, 0.9% sodium chloride injection is used. For hypotonic dehydration, a high concentration of 3%-5% NaCl injection is used. Sodium chloride injection can also be used as a topical application, for topical wound irrigation.