The main causes of acid heartburn include physiological factors, such as overeating, and pathological factors, such as gastroesophageal reflux, gastritis, gastric ulcer, angina pectoris, heart attack, gastric cancer and other diseases. 1. Physiological factors: recent improper diet, such as drinking alcohol, eating too much, indigestion, eating too greasy and stimulating food, or emotional excitement, may cause excessive secretion of gastric acid, acid heartburn symptoms. 2. Gastroesophageal reflux (GERD): It is mainly due to the relaxation of the lower esophageal sphincter, which leads to the reflux of food and acid from the stomach into the esophagus, thus damaging the mucosa of the gastroesophagus and leading to acid heartburn, etc. It usually occurs after eating. 3. Gastritis, gastric ulcer: mainly due to the destruction of gastric mucosa, resulting in gastric acid secretion, directly stimulate the gastric mucosa, causing gastric mucosal damage aggravated, resulting in acid heartburn and other discomforts. 4. Angina pectoris, heart attack: sometimes when patients have sudden angina pectoris, heart attack, because the heart is located in the back of the sternum, there will also be acid reflux and heartburn and other pain, which is mistaken for stomach lesions. 5. Gastric cancer: gastric cancer causes ischemic necrosis of gastric mucous membrane wall and its surrounding area, which leads to severe acid reflux, heartburn and other discomforts when stimulated by gastric acid. In addition, there may be other reasons for heartburn, so it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of doctors.