A ring-shaped muscle (sphincter) between the stomach and esophagus normally helps prevent regurgitation. Regurgitation of sour-tasting or bitter-tasting material can result from acid coming up from the stomach. Regurgitation of tasteless fluid containing mucus or undigested food can result from a narrowing (stricture) or a blockage of the esophagus Overview of Esophageal Obstructions The esophagus (the hollow tube that leads from the throat to the stomach) can be narrowed or completely obstructed (blocked). In most cases, the cause is Progression of an injury to the esophagus... read more or from an abnormal pouch in the esophagus called a Zenker diverticulum Zenker diverticula (pharyngeal diverticula) Esophageal diverticula are abnormal pouches or pockets in the esophagus. Rarely, they cause swallowing difficulties and regurgitation (the spitting up of food without nausea or forceful contractions... read more 
. The blockage may result from acid damage to the esophagus, ingestion of caustic substances, cancer of the esophagus Esophageal Cancer Esophageal cancers develop in the cells that line the wall of the esophagus (the tube that connects the throat to the stomach). Tobacco and alcohol use, gastroesophageal reflux, and obesity... read more 
, or abnormal nerve control that interferes with coordination between the esophagus and its sphincter at the opening to the stomach (achalasia Achalasia Achalasia is a disorder in which the rhythmic contractions of the esophagus (called peristalsis) are missing or impaired, the lower esophageal sphincter does not relax normally, and the resting... read more ).
Rumination
Regurgitation sometimes occurs with no apparent physical cause. Such regurgitation is called rumination. In rumination, small amounts of food are regurgitated from the stomach, usually 15 to 30 minutes after eating. The material often passes all the way to the mouth where a person may chew it again and reswallow it. Rumination is usually involuntary and occurs without nausea, pain, or difficulty in swallowing.
Rumination is common among infants. In adults, rumination most often occurs among people who have emotional disorders, especially during periods of stress.
Rumination may be helped by doing behavioral techniques such as relaxation Relaxation Techniques Relaxation, a type of mind-body medicine, includes practices specifically designed to relieve tension and stress. The specific technique may be aimed at the following: Controlling the stress... read more , biofeedback Biofeedback Biofeedback, a type of mind-body medicine, is a method of bringing unconscious biologic processes under conscious control. In biofeedback, electronic devices are used to measure and report information... read more , or training in how to use the diaphragm instead of chest muscles to breathe. A drug called baclofen is used to relax muscles and may be given to some people. For some people, an evaluation by a psychiatrist may be helpful.
