GERD is a chronic digestive disease. GERD happens when a muscle at the end of your esophagus does not close properly. GERD occurs when stomach acid or, occasionally, stomach content, flows back into your food pipe (esophagus). The backwash (reflux) irritates the lining of your esophagus and causes GERD. Both acid reflux and heartburn are common digestive conditions that many people experience from time to time. When these signs and symptoms occur at least twice each week or interfere with your daily life, or when your doctor can see damage to your esophagus, you may be diagnosed with GERD. Most people can manage the discomfort of GERD with lifestyle changes and over-the-counter medications. But some people with GERD may need stronger medications, or even surgery, to reduce symptoms.
Gastroesophageal Reflux Disease (GERD), Mayo Clinic (Mar. 9, 2018), https://www.mayoclinic.org/diseases-conditions/gerd/symptoms-causes/syc-20361940