A saline solution is a mixture of salt and water, typically containing sodium chloride. It is commonly used in medical settings for various purposes, such as rehydrating patients, cleaning wounds, and delivering medications. The concentration of salt in saline solutions can vary, with normal saline containing 0.9% sodium chloride. Saline solutions are also used in laboratories and for contact lens care. They help maintain the proper balance of fluids in the body and can be used in procedures like intravenous therapy. Overall, saline solutions play a crucial role in both healthcare and everyday applications.