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 or from an abnormal pouch in the esophagus called a Zenker diverticulum. The blockage may result from acid damage to the esophagus, ingestion of caustic substances, cancer of the esophagus, or abnormal nerve control that interferes with coordination between the esophagus and its sphincter at the opening to the stomach (achalasia).
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, biofeedback, 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.