Malodorous acid refers to the patient’s bad taste of sour food, after eating then acid reflux, heartburn, caused by peptic ulcer, chronic gastritis …… malodorous acid is an important disease that can affect people’s lives for a long time. The incidence is on the rise, and tends to be younger, this disease that also brings great harm to people, once the lack of proper care is easy to relapse. So how is the diagnosis of bad acidophagia? Here is a brief introduction for you. How to diagnose malodorous acid (1) chronic course, periodic attacks, often related to seasonal changes, mental factors, improper diet; or long-term use of drugs that can cause ulcers such as aspirin, etc. (2) Vague, burning or dull pain in the epigastrium, relieved by alkaline medication. The typical gastric ulcer is usually located to the left of the subxiphoid process and occurs half an hour to one to two hours after a meal. The pain is often accompanied by acid reflux and belching. (3) Basal and maximal acid secretion measurements are useful for diagnosis. The basal acid secretion is normal or slightly low in malodorous acid products, but it should not be free acid deficiency. (4) Positive fecal occult blood in the active phase of malignant acidophagus. (5) Direct signs such as niche shadow and concentration of mucosal folds can be seen on barium X-ray examination. Indirect signs such as local pressure pain alone, irritation deformation are only for reference. (6) Gastroscopy, round or elliptical ulcers with flat base and neat margins can be seen in the stomach. Patients are advised to go to the hospital for systematic examination and treatment as soon as the suspected symptoms appear, so as not to delay the disease.