Non-Erosive Reflux Disease (NERD) is a type of gastroesophageal reflux disease (GERD) where there is no visible damage to the esophagus. It is characterized by symptoms such as heartburn, regurgitation, and chest pain, but without the presence of erosions or ulcers. NERD is typically treated with lifestyle changes, proton pump inhibitors, or other medications to reduce acid reflux.