Intravenous injection is a medical procedure where a needle is inserted into a vein to deliver fluids, medications, or nutrients directly into the bloodstream. This method allows for rapid absorption and immediate effects, making it useful in emergencies or for patients who cannot take medications orally. The procedure typically involves cleaning the skin, inserting a needle into a vein, and connecting it to an infusion device or syringe. Healthcare professionals monitor the injection site and the patient's response to ensure safety and effectiveness. Intravenous injections are commonly used in hospitals and clinics for various treatments.