Gastroesophageal reflux disease (gastroesophageal reflux) is an illness caused by incorrect functioning of the sphincter between the esophagus and the stomach. The stomach content permanently reaches the esophageal mucous membrane causing its damage and corrosion. This disease is also partly caused by increased secretion of stomach acid. Increased acid secretion is stimulated by some inappropriate foodstuffs, namely by coffee, acid beverages, and often by sweet and greasy food. However, stomach acid secretion is most increased by stress and mental strain. Stomach acid ingress into the esophagus is exacerbated by hiatal hernia. Heartburn in a well-known symptom of this condition. However, there are many patients not suffering from heartburn. Despite that, without knowing they have severe reflux disease with the damaged esophagus or laryngeal and respiratory symptoms and signs. Such a condition is called extraesophageal reflux.