Intravenous means "within a vein." It usually refers to giving medications or fluids through a needle or tube inserted into a vein. This allows immediate access to the blood supply. For example, your doctor may prescribe medications to be given through a vein, or an intravenous (IV) line.
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.