Waterbrash, or pyrosis. A symptom of ‘indigestion’ when the mouth fills with tasteless or sour fluid, which is mostly saliva, but may contain some gastric juice brought up from the stomach. This is accompanied by a burning pain often felt at the pit of the stomach or in the chest. The condition is a symptom of excessive acidity of the stomach contents, due sometimes to an injudicious diet, and often characteristic of a DUODENAL ULCER. (See also DYSPEPSIA.)