Heartburn after eating is related to gastritis, gastric ulcer, and reflux esophagitis. Patients with gastritis will have congestion and edema on the gastric mucosa. These people will cause frictional stimulation to the gastric mucosa during the process of food digestion after eating, and it will lead to pain in the stomach, and since the stomach and the heart are closer, some people mistake it for pain in the heart area. Patients with gastric ulcer will stimulate the secretion of gastric acid about an hour after eating food because of the digestion of food, therefore it will lead to excessive secretion of gastric acid. When the gastric acid comes in contact with the ulcer surface, it will cause corrosion of the ulcer surface, thus inducing pain in the chest area, and the nature of the pain is more intense in patients. Some people have reflux esophagitis, and these people also have excessive secretion of stomach acid that can reflux into the esophagus, causing heartburn and pain.