Hidden pain below the left rib cage can be seen in the following conditions: i. Left pneumonia or pleurisy, which presents with inflammation of the lower left lung, which can involve the pleura and cause respiratory-related chest pain. Patients experience increased chest pain when coughing, deep inspiration and turning position, and the chest pain can be reduced or disappeared when holding the breath. Second, in coronary artery disease, paroxysmal chest pain can occur in the apical region, that is, below the rib cage of the left chest, often seen in angina pectoris or acute myocardial infarction. Anginal pain is short-lived, usually lasting several minutes, and can be relieved by resting or containing nitroglycerin. In acute myocardial infarction, the pain is longer and can last for more than ten minutes or even several hours, and an electrocardiogram and myocardial enzyme profile can be done to clarify the diagnosis. Third, pain below the left rib cage is also seen in gastritis, gastric ulcer, etc. Patients may have nausea, vomiting, acid reflux, belching and other symptoms. Gastroscopy is recommended to make a clear diagnosis.