A transfusion is a medical procedure where blood or blood components are transferred from one person to another. This is often done to replace lost blood due to surgery, injury, or illness. The blood used in transfusions is carefully matched to ensure compatibility, reducing the risk of adverse reactions. There are different types of transfusions, including red blood cell transfusions, which help improve oxygen delivery in the body, and platelet transfusions, which assist in blood clotting. Medical professionals monitor patients closely during and after the procedure to ensure their safety and well-being.