Retching

Retching is a process in the human body where gastric (and sometimes duodenal) contents are forced into the esophagus, but do not enter the pharynx. Retching usually precedes vomiting, and is known as the first phase of vomiting or the Milrah Phase - when the upper esophageal sphincter remains closed. If the upper esophageal sphincter is open, vomiting occurs.It is usually caused by a bad smell or choking.

At times, however, the term is used almost synonymously with vomiting.