Reflux occurs when stomach contents flow back up for any reason. There are two types of reflux.
- Gastroesophageal reflux (stomach reflux) – the backflow of stomach contents into the lower part of the esophagus
- Laryngopharyngeal reflux (throat reflux) – the backflow of stomach contents into the throat, nasopharynx, and vocal cords
The lower part of the esophagus is partially resistant to the acid and digestive enzymes secreted by the stomach. It is nearly normal for stomach contents to reflux into the lower part of the esophagus up to 20–30 times a day. Since the throat is not resistant to stomach acid and digestive enzymes, contact with these substances causes swelling and increased secretion in the throat, vocal cords, and the entrance to the esophagus.