Acid refers to stomach acid, and waking up from a mouthful of stomach acid while asleep may be caused by reflux esophagitis, gastritis and other factors. 1. Reflux esophagitis: In some patients, the nerves may be in a state of excitement during sleep, leading to relaxation of the esophageal sphincter, which is prone to acid reflux, causing the symptom of waking up from sleep and choking on stomach acid. When stimulated by gastric acid, pepsin and other reflux material, it is easy to cause reflux esophagitis and other diseases. If the disease is not treated in time, it may cause further aggravation of reflux of gastric contents and even develop into precancerous lesions. 2. Acute and chronic gastritis: After the stomach is infected by Helicobacter pylori, it can cause acute and chronic gastritis. After the gastric mucosa is stimulated by inflammation, it may secrete too much gastric acid, and then the digestive juices may reflux into the esophagus and cause the above symptoms. Waking up from a mouthful of acid while asleep may also be caused by other reasons, and patients should go to the hospital in a timely manner.