Regurgitation occurs when food comes up into the mouth from the stomach or esophagus without forceful abdominal muscle contractions or nausea. Rumination means regurgitation is frequently occurring with no apparent physical cause other than involuntary habit. This regurgitation in patients with rumination syndrome usually occurs between fifteen and thirty minutes after the ingestion of food and can be described as effortless. The food does not taste particularly sour to affected individuals.
The best explanation for this type of regurgitation is that voluntary but subconscious contractions of the abdominal wall cause an increased amount of pressure and simultaneous relaxation of the sphincter in the esophagus. After the food reaches the mouth again, the patient re-chews it, and they either swallow or spit it out. The circumstances of the individual at the time of the regurgitation usually influence the decision to either swallow or spit the regurgitant. Food does not regurgitate when a rumination syndrome patient is asleep. Individuals with this disorder also do not respond to treatments for gastroesophageal reflux disease.