Acid reflux is caused by the reflux of gastric juice into the esophagus beyond the normal limit. Common causes include dietary factors such as overeating; and pathological factors such as relaxation of the lower esophageal sphincter. 1. Dietary factors: excessive pressure in the stomach caused by eating too much or too fast can lead to acid-containing gastric secretions or bile retrogressing from the stomach into the esophagus, resulting in acid reflux and other uncomfortable symptoms. 2. Lower esophageal sphincter relaxation: Functional or mechanical relaxation of the lower esophageal sphincter can lead to reflux of acidic contents in the stomach, resulting in acid reflux symptoms. Some foods and drugs can cause temporary relaxation of the lower esophageal sphincter, such as coffee, alcohol, chocolate, fat, cigarettes, nitroglycerin, nifedipine and so on. If patients have symptoms of acid reflux, they need to go to the hospital in time for relevant examinations to clarify the cause of the disease and standardize the treatment, so as not to delay the condition.