The functions of sodium chloride injection include replenishing fluids, regulating the water-electrolyte balance of the body, as well as acting as a carrier of drugs to dissolve drugs and flush wounds. 1. Supplementation of fluids: Sodium chloride injection can be used to replenish body fluids, for various reasons and induced by the symptoms of water loss, whether hypotonic, isotonic and hypertonic water loss, can be injected with sodium chloride injection to replenish fluids. 2. Sodium chloride injection can regulate the body’s water-electrolyte balance, in which chloride ions and sodium ions are an important part of the body, and play an important role in maintaining normal plasma and extracellular fluid osmotic pressure. 3. Solvent drugs: can be used as a carrier to dissolve drugs, such as intravenous injection, can be used as a solvent to promote drug delivery into the body, play a therapeutic role. 4. Sodium chloride injection can be used to flush wounds, wash the eyes and nose and so on. Common adverse symptoms of Sodium Chloride Injection include chest tightness, rapid heart rate and dyspnea when infused too quickly, and should be used under the guidance of a specialist.