Reflux occurs if the stomach contents go up for any reason. There are two types of reflux.

• Gastroesophageal reflux (gastric reflux) – leakage of stomach contents into the lower part of the esophagus

• Laryngopharyngeal reflux (throat reflux) – escape of stomach contents to the throat, nasal passages and vocal cords
  The lower part of the esophagus is partially resistant to acid and digestive enzymes secreted from the stomach. It is almost normal for stomach contents to escape 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 of this content with the throat causes edema and secretions to increase in the vocal cords and the entrance of the esophagus.

Source: http://www.kbb.org.tr