Intravenous fluids are sterile liquids administered directly into a person's bloodstream through a small tube called a catheter. They are commonly used in hospitals to provide hydration, deliver medications, or supply essential nutrients when a patient cannot eat or drink normally. These fluids come in various types, including saline solutions, which contain salt, and dextrose solutions, which provide sugar. The choice of fluid depends on the patient's specific needs, such as correcting dehydration, maintaining electrolyte balance, or supporting overall health during medical treatment.