GERD laryngitis can cause phlegm. Since the esophagus is connected to the pharynx, when stomach acid refluxes into the esophagus, it continues to reflux into the pharynx, which can irritate the pharynx and cause phlegm, but the cause of phlegm is not only gastroesophageal reflux. GERD laryngitis usually leads to phlegm, and the main reason is that the esophagus is connected to the pharynx. When the patient has too much stomach acid, the acid will reflux into the esophagus, and then continue to reflux into the pharynx. A large amount of stomach acid will stimulate the mucous membrane of the throat, leading to excessive mucus secretion, which in turn causes an increase in phlegm. It is important to note that if the symptoms of increased phlegm are more serious, please seek medical advice and consult your doctor to identify the cause of the problem and treat it with medication under the doctor’s guidance.