Saline solutions are mixtures of salt (sodium chloride) and water, commonly used in medical settings. They help maintain fluid balance in the body and are often used for hydration, wound cleaning, and as a vehicle for medications. The concentration of salt in saline solutions can vary, with normal saline containing 0.9% sodium chloride. These solutions are also used in laboratory settings for various experiments and procedures. In addition to sodium chloride, saline can include other components, such as potassium chloride or calcium chloride, depending on the specific medical or research needs.