Intravenous solutions are sterile liquids administered directly into a patient's bloodstream through a venous catheter. They are used to provide hydration, deliver medications, and supply essential nutrients. Common types include saline, dextrose, and lactated Ringer's solution, each serving specific medical purposes. These solutions help maintain fluid balance, support electrolyte levels, and can be crucial during surgeries or for patients unable to consume food or fluids orally. Proper administration and monitoring are essential to prevent complications, ensuring that patients receive the right amount of fluids and nutrients for their health needs.