**1. Introduction**

Gastroesophageal reflux disease (GERD), commonly known as heartburn, has been one of the most prevalent digestive disorders for the past few decades. Despite various definitions in different parts of the world, GERD generally refers to the effortless movement of stomach contents into the esophagus causing troublesome symptoms, typically a burning sensation in the chest, which may radiate toward the neck, throat, and the back, inducing pain. Chronic GERD can lead to several complications, including erosive esophagitis, esophageal strictures, and esophageal epithelial transformation into Barrett's Esophagus (squamous epithelium turning into columnar epithelium), a precancerous condition to adenocarcinoma. Therefore, early diagnosis and proper treatment are critical for the prevention of these potential complications and malignancy. Due to its popularity, GERD has not only deteriorated the quality of life for many people all over the world, but it has also brought up tremendous economic pressure on many countries and regions. European Digestive Health Summit 2018 reported a 26% reduction in productivity across Europe because of GERD, costing employers ~\$4.4 billion [1]. In the United States, the expenses on GERD were estimated to be at least \$24 billion/year [2].
