Saline is an aqueous solution that contains 0.9% sodium chloride (NaCl). Due to its composition, it is ideal for use in medicine, as it is safe and does not irritate body tissues. It is used for various purposes, such as cleaning wounds, rinsing eyes, nose or ears, rehydrating the body, and as a carrier of drugs in infusions. The physiological solution is sterile and without preservatives, which means it does not cause allergic reactions or irritation.