A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it.

They may also be used to take liquid samples from the body, for example taking blood from a vein in venipuncture.

Large bore hypodermic intervention is especially useful in catastrophic blood loss or shock.

A hypodermic needle is used for rapid delivery of liquids, or when the injected substance cannot be ingested, either because it would not be absorbed (as with insulin), or because it would harm the liver.