The medical procedure of injecting blood or blood components from a healthy donor into a patient's bloodstream, typically to treat severe blood loss, anemia, or other medical conditions requiring additional blood supply, ensuring compatibility of blood types.

The act of administering blood directly into a patient's veins as a therapeutic measure, which is necessary for recovery in situations such as surgery, trauma, or certain illnesses, while requiring careful matching of blood types for safety.

A clinical intervention involving the transfer of blood products harvested from a healthy individual into a patient’s vascular system, aimed at restoring the patient's blood volume or improving blood-related health issues.