The stomach secretes acid to digest food. Special valve systems prevent stomach contents from flowing back into the esophagus. When the lower esophageal sphincter (LES), located between the stomach and the esophagus, does not function properly, the acidic contents of the stomach flow back into the esophagus. This condition is called Gastroesophageal Reflux (GER). If the upper esophageal sphincter (UES), located between the esophagus and the throat, also loses its function, stomach contents – including acid and sometimes bile – can reach the much more sensitive throat, larynx, and vocal cords. This condition is known as Laryngopharyngeal Reflux (LPR) or, commonly, 'throat reflux'. LPR differs from common stomach reflux (GER); LPR is generally more pronounced during the day and in an upright position, whereas GER is more frequent and bothersome when lying down. The hypersensitivity of laryngeal and pharyngeal tissues, certain nervous reflexes, and esophageal motility play a significant role in the development of LPR. Voice problems related to reflux can arise either due to the direct irritative effect of acid or the reflex contraction and tension of the throat, laryngeal, and neck muscles in response to acid.