Rumination is part of the digestive process of animals that have a four-compartment stomach, such as cattle, goats, sheep, and deer. Food is initially swallowed and mixed in the proximal two chambers of the stomach. It then moves back into the mouth where it is chewed and re-swallowed. In humans, rumination syndrome, or rumination disorder, refers to a chronic condition whereby recently consumed food is effortlessly regurgitated back into the mouth, in the absence of nausea, retching, heartburn, or abdominal pain. Initially documented in children and intellectually challenged persons, this disorder is now recognized to occur in individuals of all ages and cognitive abilities. It has a female preponderance and has been associated with depression and bulimia nervosa, though its presence in bulimia nervosa has ...