An endotracheal tube, also known as an ET tube, is a flexible tube that is placed in the trachea (windpipe) through the mouth or nose. It is used to either assist with breathing during surgery or support breathing in people with lung disease, heart failure, chest trauma, or an airway obstruction.

The process of inserting an ET tube is called endotracheal intubation (EI). Medications can be given to reduce discomfort and make the placement to the tube easier. For emergency situations, ET tubes are almost always inserted through the mouth.