Isotonic saline is a sterile solution of sodium chloride (salt) in water, typically containing 0.9% salt. It is called "isotonic" because its salt concentration is similar to that of the body's cells, which helps maintain fluid balance. This solution is commonly used in medical settings for hydration, wound cleaning, and as a vehicle for delivering medications. In addition to its use in hospitals, isotonic saline is also employed in various laboratory procedures and research. It is important for maintaining the proper osmotic pressure in cells, making it essential for many biological and physiological processes.