A solution consisting of a salt such as sodium chloride (common table salt, NaCl) dissolved in water. Saline solutions are often used by emergency personnel to give fluids intravenously (from a bag through a needle in your arm, for example) and to give gastric lavage when a poison has been ingested. A more common everyday use of saline is for the rinsing of contact lenses. Additional Info: When a person receives fluids intravenously (through an IV bag, for example), a salinesolution is sometime used. Giving large amounts of pure water directly into a vein would cause your blood cells to become hypotonic, possibly leading to death. Saline solutions can also be used to rinse the eyes to relieve irritation or remove foreign objects and/or chemicals. The water in emergency eye wash bottles may or may not be saline, but should contain a chemical preservative of some sort to prevent the growth of bacteria, fungus, algae, and a canthamoeba which could result in an eye infection. Note that simple eye wash bottles, while they may provide some immediate relief in an emergency, have a very limited capacity and do not meet ANSI or OSHA requirements for emergency eye washes. See: The link to Guardian Equipment under Further Reading or our entry on eye washes for more on ANSI eye wash requirements. MSDS Relevance: You will usually find this word in reference to recommended medical procedures. In general, these should only be performed by trained medical personnel. See also: Catharsis, Electrolyte, Eye Wash, Halogen, Intravenous