Intravenous means "within a vein." Most often it refers to giving medicines or fluids through a needle or tube inserted into a vein. This allows the medicine or fluid to enter your bloodstream right away. For example, your health care provider may prescribe medicines to be given through a vein, or an intravenous (IV) line.
Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.