A plunger is a common device that is used to release stoppages in plumbing. The tool consists of a rubber cup with an attached stick "shaft", usually made of wood or bronze. Before use, any objects such as hair in the plug grate should be removed and, if possible the overflow hole should be sealed with a wet cloth. The cup is pushed down against the drain, and either pressed hard into the drain to force air in, or is pushed down until the rubber cup is flattened, then pulled out, causing a vacuum. The intent is to loosen or break up a clog, excessive material, or other blockage in the outlet or drainage pipe from a sink, toilet, bathtub, shower, etc.

The difference between a sink (kitchen) plunger and a toilet plunger is that the former looks like a ball cut in half while the latter looks more like a distorted ball with a large hole on the bottom.

A plunger is much more effective when there is water in the pipe because water does not compress and will thus transmit more of the applied force than air.